1.
Glyceride
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Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids. Glycerol has three functional groups, which can be esterified with one, two, or three fatty acids to form monoglycerides, diglycerides, and triglycerides. Vegetable oils and animal fats contain mostly triglycerides, but are broken down by enzymes into mono and diglycerides and free fatty acids. Soaps are formed from the reaction of glycerides with sodium hydroxide, the product of the reaction is glycerol and salts of fatty acids. Fatty acids in the soap emulsify the oils in dirt, enabling the removal of dirt with water. Partial glycerides are esters of glycerol with fatty acids, where not all the groups are esterified. Since some of their groups are free their molecules are polar. Partial glycerides may be monoglycerides or diglycerides, the most common forms of acylglycerol are triglycerides, having high caloric value and usually yielding twice as much energy per gram as carbohydrate. An acylglyceride linkage is the covalent bond between the acid groups and one of the three hydroxyl groups of glycerol
2.
Fatty acid
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In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with a long aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms. Fatty acids are derived from triglycerides or phospholipids. Fatty acids are important dietary sources of fuel for animals because, many cell types can use either glucose or fatty acids for this purpose. Fatty acids that have double bonds are known as unsaturated. Fatty acids without double bonds are known as saturated and they differ in length as well. Fatty acid chains differ by length, often categorized as short to very long, short-chain fatty acids are fatty acids with aliphatic tails of five or fewer carbons. Medium-chain fatty acids are fatty acids with aliphatic tails of 6–12 carbons, long-chain fatty acids are fatty acids with aliphatic tails of 13 to 21 carbons. Very long chain fatty acids are fatty acids with aliphatic tails of 22 or more carbons, unsaturated fatty acids have one or more double bonds between carbon atoms. The two carbon atoms in the chain that are next to either side of the double bond can occur in a cis or trans configuration. Cis A cis configuration means that the two atoms adjacent to the double bond stick out on the same side of the chain. The rigidity of the double bond freezes its conformation and, in the case of the cis isomer, causes the chain to bend, the more double bonds the chain has in the cis configuration, the less flexibility it has. When a chain has many cis bonds, it becomes quite curved in its most accessible conformations, for example, oleic acid, with one double bond, has a kink in it, whereas linoleic acid, with two double bonds, has a more pronounced bend. α-Linolenic acid, with three bonds, favors a hooked shape. Trans A trans configuration, by contrast, means that the adjacent two hydrogen atoms lie on opposite sides of the chain, as a result, they do not cause the chain to bend much, and their shape is similar to straight saturated fatty acids. In most naturally occurring unsaturated fatty acids, each bond has three n carbon atoms after it, for some n, and all are cis bonds. Most fatty acids in the configuration are not found in nature and are the result of human processing. Fatty acids that are required by the body but cannot be made in sufficient quantity from other substrates
3.
Covalent bond
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A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, for many molecules, the sharing of electrons allows each atom to attain the equivalent of a full outer shell, corresponding to a stable electronic configuration. Covalent bonding includes many kinds of interactions, including σ-bonding, π-bonding, metal-to-metal bonding, agostic interactions, bent bonds, the term covalent bond dates from 1939. In the molecule H2, the atoms share the two electrons via covalent bonding. Covalency is greatest between atoms of similar electronegativities, thus, covalent bonding does not necessarily require that the two atoms be of the same elements, only that they be of comparable electronegativity. Covalent bonding that entails sharing of electrons more than two atoms is said to be delocalized. The term covalence in regard to bonding was first used in 1919 by Irving Langmuir in a Journal of the American Chemical Society article entitled The Arrangement of Electrons in Atoms and Molecules. Langmuir wrote that we shall denote by the term covalence the number of pairs of electrons that an atom shares with its neighbors. The idea of covalent bonding can be traced several years before 1919 to Gilbert N. Lewis and he introduced the Lewis notation or electron dot notation or Lewis dot structure, in which valence electrons are represented as dots around the atomic symbols. Pairs of electrons located between atoms represent covalent bonds, multiple pairs represent multiple bonds, such as double bonds and triple bonds. An alternative form of representation, not shown here, has bond-forming electron pairs represented as solid lines, Lewis proposed that an atom forms enough covalent bonds to form a full outer electron shell. In the diagram of methane shown here, the atom has a valence of four and is, therefore, surrounded by eight electrons, four from the carbon itself. Each hydrogen has a valence of one and is surrounded by two electrons – its own one electron plus one from the carbon, walter Heitler and Fritz London are credited with the first successful quantum mechanical explanation of a chemical bond in 1927. Their work was based on the valence bond model, which assumes that a bond is formed when there is good overlap between the atomic orbitals of participating atoms. Atomic orbitals have specific directional properties leading to different types of covalent bonds, sigma bonds are the strongest covalent bonds and are due to head-on overlapping of orbitals on two different atoms. A single bond is usually a σ bond, pi bonds are weaker and are due to lateral overlap between p orbitals. A double bond between two given atoms consists of one σ and one π bond, and a bond is one σ. Covalent bonds are also affected by the electronegativity of the atoms which determines the chemical polarity of the bond
4.
Glycerol
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Glycerol /ˈɡlɪsərɒl/ is a simple polyol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting, the glycerol backbone is found in all lipids known as triglycerides. It is widely used in the industry as a sweetener and humectant. Glycerol has three groups that are responsible for its solubility in water and its hygroscopic nature. Although achiral, glycerol is prochiral with respect to reactions of one of the two primary alcohols, thus, in substituted derivatives, the stereospecific numbering labels each carbon as either sn-1, sn-2, or sn-3. Glycerol is generally obtained from plant and animal sources where it occurs as triglycerides, triglycerides are esters of glycerol with long-chain carboxylic acids. Approximately 950,000 tons per year are produced in the United States and it was projected in 2006 that by the year 2020, production would be six times more than demand. Glycerol from triglycerides is produced on a scale, but the crude product is of variable quality. It can be purified, but the process is expensive, some glycerol is burned for energy, but its heat value is low. High purity glycerol is obtained by distillation, vacuum is helpful due to the high boiling point of glycerol. Although usually not cost-effective, glycerol can be produced by various routes from propylene and this epichlorohydrin is then hydrolyzed to give glycerol. Chlorine-free processes from propylene include the synthesis of glycerol from acrolein, because of the large-scale production of biodiesel from fats, where glycerol is a waste product, the market for glycerol is depressed. Thus, synthetic processes are not economical, owing to oversupply, efforts are being made to convert glycerol to synthetic precursors, such as acrolein and epichlorohydrin. In food and beverages, glycerol serves as a humectant, solvent, and sweetener and it is also used as filler in commercially prepared low-fat foods, and as a thickening agent in liqueurs. Glycerol and water are used to preserve certain types of plant leaves, as a sugar substitute, it has approximately 27 kilocalories per teaspoon and is 60% as sweet as sucrose. It does not feed the bacteria that form plaques and cause dental cavities, as a food additive, glycerol is labeled as E number E422. It is added to icing to prevent it from setting too hard, as used in foods, glycerol is categorized by the Academy of Nutrition and Dietetics as a carbohydrate. The U. S. Food and Drug Administration carbohydrate designation includes all caloric macronutrients excluding protein, glycerol is used in medical, pharmaceutical and personal care preparations, mainly as a means of improving smoothness, providing lubrication, and as a humectant
5.
Ester
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In chemistry, esters are chemical compounds derived from an acid in which at least one –OH group is replaced by an –O–alkyl group. Usually, esters are derived from an acid and an alcohol. Glycerides, which are fatty acid esters of glycerol, are important esters in biology, being one of the classes of lipids. Esters with low weight are commonly used as fragrances and found in essential oils. Phosphoesters form the backbone of DNA molecules, nitrate esters, such as nitroglycerin, are known for their explosive properties, while polyesters are important plastics, with monomers linked by ester moieties. The word ester was coined in 1848 by German chemist Leopold Gmelin, probably as a contraction of the German Essigäther, ester names are derived from the parent alcohol and the parent acid, where the latter may be organic or inorganic. Esters derived from more complex carboxylic acids are, on the hand, more frequently named using the systematic IUPAC name. For example, the ester hexyl octanoate, also known under the trivial name hexyl caprylate, has the formula CH36CO25CH3, the chemical formulas of organic esters usually take the form RCO2R′, where R and R′ are the hydrocarbon parts of the carboxylic acid and the alcohol, respectively. For example, butyl acetate, derived from butanol and acetic acid would be written CH3CO2C4H9, alternative presentations are common including BuOAc and CH3COOC4H9. Cyclic esters are called lactones, regardless of whether they are derived from an organic or an inorganic acid, one example of a lactone is γ-valerolactone. An uncommon class of organic esters are the orthoesters, which have the formula RC3, triethylorthoformate is derived, in terms of its name from orthoformic acid and ethanol. Esters can also be derived from an acid and an alcohol. For example, triphenyl phosphate is the derived from phosphoric acid. Organic carbonates are derived from acid, for example, ethylene carbonate is derived from carbonic acid. So far an alcohol and inorganic acid are linked via oxygen atoms, in corollary, boron features borinic esters, boronic esters, and borates. As oxygen is a group 16 chemical element, sulfur atoms can replace some oxygen atoms in carbon–oxygen–central inorganic atom covalent bonds of an ester, esters contain a carbonyl center, which gives rise to 120 ° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier and their flexibility and low polarity is manifested in their physical properties, they tend to be less rigid and more volatile than the corresponding amides. The pKa of the alpha-hydrogens on esters is around 25, the preference for the Z conformation is influenced by the nature of the substituents and solvent, if present
6.
Surfactants
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Surfactants are compounds that lower the surface tension between two liquids or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, the term surfactant is a blend of surface active agent. In the United States National Library of Medicines Medical Subject Headings vocabulary, for the more general meaning, surface active agent/s is the heading. Surfactants are usually organic compounds that are amphiphilic, meaning they contain both hydrophobic groups and hydrophilic groups, therefore, a surfactant contains both a water-insoluble component and a water-soluble component. Surfactants will diffuse in water and adsorb at interfaces between air and water or at the interface between oil and water, in the case where water is mixed with oil. The water-insoluble hydrophobic group may extend out of the water phase, into the air or into the oil phase. World production of surfactants is estimated at 15 Mton/y, of which half are soaps. Other surfactants produced on a large scale are linear alkylbenzenesulfonates, lignin sulfonates, fatty alcohol ethoxylates. Other types of aggregates can also be formed, such as spherical or cylindrical micelles or lipid bilayers, the shape of the aggregates depends on the chemical structure of the surfactants, namely the balance in size between hydrophilic head and hydrophobic tail. A measure of this is the HLB, Hydrophilic-lipophilic balance, Surfactants reduce the surface tension of water by adsorbing at the liquid-air interface. The relation that links the surface tension and the excess is known as the Gibbs isotherm. The dynamics of adsorption depend on the coefficient of the surfactant. As the interface is created, the adsorption is limited by the diffusion of the surfactant to the interface, in some cases, there can exist an energetic barrier to adsorption or desorption of the surfactant. If such a barrier limits the rate, the dynamics are said to be ‘kinetically limited. Such energy barriers can be due to steric or electrostatic repulsions, the surface rheology of surfactant layers, including the elasticity and viscosity of the layer, play an important role in the stability of foams and emulsions. Interfacial and surface tension can be characterized by classical methods such as the -pendant or spinning drop method, surface rheology can be characterized by the oscillating drop method or shear surface rheometers such as double-cone, double-ring or magnetic rod shear surface rheometer. In solution, detergents help solubilize a variety of species by dissociating aggregates. Popular surfactants in the laboratory are SDS and CTAB
7.
Emulsion
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An emulsion is a mixture of two or more liquids that are normally immiscible. Emulsions are part of a general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids, in an emulsion, one liquid is dispersed in the other. Examples of emulsions include vinaigrettes, homogenized milk, mayonnaise, the word emulsion comes from the Latin word for to milk, as milk is an emulsion of fat and water, along with other components. Two liquids can form different types of emulsions, as an example, oil and water can form, first, an oil-in-water emulsion, wherein the oil is the dispersed phase, and water is the dispersion medium. Second, they can form an emulsion, wherein water is the dispersed phase. Multiple emulsions are also possible, including a water-in-oil-in-water emulsion and an oil-in-water-in-oil emulsion, emulsions, being liquids, do not exhibit a static internal structure. The droplets dispersed in the matrix are usually assumed to be statistically distributed. The term emulsion is used to refer to the photo-sensitive side of photographic film. Such a photographic emulsion consist of silver halide colloidal particles dispersed in a gelatin matrix, nuclear emulsions are similar to photographic emulsions, except that they are used in particle physics to detect high-energy elementary particles. Emulsions contain both a dispersed and a phase, with the boundary between the phases called the interface. Emulsions tend to have an appearance because the many phase interfaces scatter light as it passes through the emulsion. Emulsions appear white when all light is scattered equally, if the emulsion is dilute enough, higher-frequency and low-wavelength light will be scattered more, and the emulsion will appear bluer – this is called the Tyndall effect. If the emulsion is concentrated enough, the color will be distorted toward comparatively longer wavelengths and this phenomenon is easily observable when comparing skimmed milk, which contains little fat, to cream, which contains a much higher concentration of milk fat. One example would be a mixture of water and oil, two special classes of emulsions – microemulsions and nanoemulsions, with droplet sizes below 100 nm – appear translucent. This property is due to the fact that lightwaves are scattered by the only if their sizes exceed about one-quarter of the wavelength of the incident light. Due to their similarity in appearance, translucent nanoemulsions and microemulsions are frequently confused, the required surfactant concentration in a microemulsion is, however, several times higher than that in a translucent nanoemulsion, and significantly exceeds the concentration of the dispersed phase. Because of many undesirable side-effects caused by surfactants, their presence is disadvantageous or prohibitive in many applications, in addition, the stability of a microemulsion is often easily compromised by dilution, by heating, or by changing pH levels
8.
Cottonseed oil
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Cottonseed oil is a cooking oil extracted from the seeds of cotton plants of various species, mainly Gossypium hirsutum and Gossypium herbaceum, that are grown for cotton fiber, animal feed, and oil. Cotton seed has a structure to other oilseeds such as sunflower seed, having an oil-bearing kernel surrounded by a hard outer hull, in processing. Cottonseed oil is used for oil, mayonnaise, salad dressing. Its fatty acid profile generally consists of 70% unsaturated fatty acids, when it is fully hydrogenated, its profile is 94% saturated fat and 2% unsaturated fatty acids. According to the oil industry, cottonseed oil does not need to be hydrogenated as much as other polyunsaturated oils to achieve similar results. Gossypol is a toxic, yellow, polyphenolic compound produced by cotton and other members of the order Malvaceae and this naturally occurring coloured compound is found in tiny glands in the seed, leaf, stem, tap root bark, and root of the cotton plant. The adaptive function of the compound facilitates natural insect resistance, the three key steps of refining, bleaching, and deodorization in producing finished oil act to eliminate the gossypol level. Ferric chloride is used to decolorize cotton seed oil. Once processed, cottonseed oil has a taste and appears generally clear with a light golden color. It has a high smoke point as a frying medium. Density ranges from 0.917 g/cm3 to 0.933 g/cm3, the by-product of cotton processing, cottonseed was considered virtually worthless before the late 19th century. While cotton production expanded throughout the 17th, 18th, and mid 19th centuries, although some of the seed was used for planting, fertilizer, and animal feed, the majority was left to rot or was illegally dumped into rivers. The increased demand for fats and oils, coupled with a decreasing supply caused prices to rise sharply, consequently, many Europeans could not afford to buy the fats and oils they had used for cooking and for lighting. Many United States entrepreneurs tried to take advantage of the increasing European demand for oils, but separating the seed hull from the seed meat proved difficult and most of these ventures failed within a few years. This problem was resolved in 1857, when William Fee invented a huller, with this new invention, cottonseed oil began to be used for illumination purposes in lamps to supplement increasingly expensive whale oil and lard. But by 1859, this use came to end as the petroleum industry emerged, cottonseed oil then began to be used illegally to fortify animal fats and lards. Initially, meat packers secretly added cottonseed oil to the pure fats, a congressional investigation followed, and legislation was passed that required products fortified with cottonseed oil to be labeled as ‘‘lard compound. ”Similarly, cottonseed oil was often blended with olive oil. Once the practice was exposed, many countries put import tariffs on American olive oil, both of these regulatory schemes depressed cottonseed oil sales and exports, once again creating an oversupply of cottonseed oil, which decreased its value
9.
Triglycerides
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A triglyceride is an ester derived from glycerol and three fatty acids. Triglycerides are the constituents of body fat in humans and other animals. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, there are many different types of triglyceride, with the main division between saturated and unsaturated types. Saturated fats are saturated with hydrogen – all available places where hydrogen atoms could be bonded to carbon atoms are occupied and these have a higher melting point and are more likely to be solid at room temperature. Unsaturated fats have double bonds between some of the atoms, reducing the number of places where hydrogen atoms can bond to carbon atoms. These have a melting point and are more likely to be liquid at room temperature. Triglycerides are chemically tri esters of fatty acids and glycerol. Triglycerides are formed by combining glycerol with three fatty acid molecules, organic acids have a carboxyl group. Alcohols and organic acids join to form esters, the glycerol molecule has three hydroxyl groups. Each fatty acid has a carboxyl group, the chain lengths of the fatty acids in naturally occurring triglycerides vary, but most contain 16,18, or 20 carbon atoms. Bacteria, however, possess the ability to synthesise odd- and branched-chain fatty acids, as a result, ruminant animal fat contains odd-numbered fatty acids, such as 15, due to the action of bacteria in the rumen. Many fatty acids are unsaturated, some are polyunsaturated, most natural fats contain a complex mixture of individual triglycerides. Because of this, they melt over a range of temperatures. Cocoa butter is unusual in that it is composed of only a few triglycerides, derived from palmitic, oleic, and stearic acids in the 1-, 2-, the simplest triglycerides are those where the three fatty acids are identical. Their names indicate the fatty acid, stearin derived from acid, palmitin derived from palmitic acid. These compounds can be obtained as three forms or polymorphs, α, β, and β′ and these forms differ in terms of their melting points. If the first and third chain R and R″ are different, then the carbon atom is a chiral centre. The pancreatic lipase acts at the bond, hydrolysing the bond. In triglyceride form, lipids cannot be absorbed by the duodenum, fatty acids, monoglycerides, and some diglycerides are absorbed by the duodenum, once the triglycerides have been broken down
10.
Vegetable
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In everyday usage, a vegetable is any part of a plant that is consumed by humans as food as part of a meal. The term vegetable is somewhat arbitrary, and largely defined through culinary and it normally excludes other food derived from plants such as fruits, nuts, and cereal grains, but includes seeds such as pulses. The original meaning of the vegetable, still used in biology, was to describe all types of plant, as in the terms vegetable kingdom. At first, plants which grew locally would have been cultivated, nowadays, most vegetables are grown all over the world as climate permits, and crops may be cultivated in protected environments in less suitable locations. China is the largest producer of vegetables and global trade in agricultural products allows consumers to purchase vegetables grown in faraway countries, the scale of production varies from subsistence farmers supplying the needs of their family for food, to agribusinesses with vast acreages of single-product crops. Depending on the type of vegetable concerned, harvesting the crop is followed by grading, storing, processing, and marketing. Vegetables can be either raw or cooked and play an important role in human nutrition, being mostly low in fat and carbohydrates. Many nutritionists encourage people to consume plenty of fruit and vegetables, the word vegetable was first recorded in English in the early 15th century. It comes from Old French, and was applied to all plants. It derives from Medieval Latin vegetabilis growing, flourishing, a change from a Late Latin meaning to be enlivening, quickening. The meaning of vegetable as a plant grown for food was not established until the 18th century, in 1767, the word was specifically used to mean a plant cultivated for food, an edible herb or root. The year 1955 saw the first use of the shortened, slang term veggie, the broadest definition is the words use adjectivally to mean matter of plant origin to distinguish it from animal, meaning matter of animal origin. More specifically, a vegetable may be defined as any plant, part of which is used for food, a secondary meaning then being the edible part of such a plant. A more precise definition is any plant part consumed for food that is not a fruit or seed, falling outside these definitions are edible fungi and edible seaweed which, although not parts of plants, are often treated as vegetables. In everyday language, the fruit and vegetable are mutually exclusive. Fruit has a precise meaning, being a part that developed from the ovary of a flowering plant. This is considerably different from the words culinary meaning, while peaches, plums, and oranges are fruit in both senses, many items commonly called vegetables, such as eggplants, bell peppers, and tomatoes, are botanically fruits. The question of whether the tomato is a fruit or a vegetable found its way into the United States Supreme Court in 1893
11.
Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
12.
Mono- and diglycerides of fatty acids
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Mono- and diglycerides of fatty acids refers to a food additive composed of diglycerides and monoglycerides which is used as an emulsifier. This mixture is sometimes referred to as partial glycerides. The raw materials of this may be vegetable or animal fats. E471 is mainly produced from oils, although animal fats are sometimes used. The fatty acids from each source are chemically identical, the Vegan Society, which discourages eating animal-based foods, flags E471 as a thing to look out for that can be animal OR non-animal based. Polyglycerol polyricinoleate Monoglyceride Diglyceride Food-Info. net, E-numbers, E471
13.
Ice cream
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Ice cream is a sweetened frozen food typically eaten as a snack or dessert. It is usually made from dairy products, such as milk and cream and it is typically sweetened with sugar or sugar substitutes. Typically, flavourings and colourings are added in addition to stabilizers, the mixture is stirred to incorporate air spaces and cooled below the freezing point of water to prevent detectable ice crystals from forming. The result is a smooth, semi-solid foam that is solid at low temperatures. It becomes more malleable as its temperature increases, the meaning of the phrase ice cream varies from one country to another. Phrases such as frozen custard, frozen yogurt, sorbet, gelato, products that do not meet the criteria to be called ice cream are labelled frozen dairy dessert instead. In other countries, such as Italy and Argentina, one word is used for all variants, analogues made from dairy alternatives, such as goats or sheeps milk, or milk substitutes, are available for those who are lactose intolerant, allergic to dairy protein, or vegan. Ice cream may be served in dishes, for eating with a spoon, or in cones, Ice cream may be served with other desserts, such as apple pie. Ice cream is used to other desserts, including ice cream floats, sundaes, milkshakes, ice cream cakes and even baked items. During the 5th century BC, ancient Greeks ate snow mixed with honey, the father of modern medicine, Hippocrates, encouraged his Ancient Greek patients to eat ice as it livens the life-juices and increases the well-being. In 400 BC, the Persians invented a special chilled food, made of water and vermicelli. The ice was mixed with saffron, fruits, and various other flavours, a frozen mixture of milk and rice was used in China around 200 BC. The Roman Emperor Nero had ice brought from the mountains and combined it with fruit toppings to create chilled delicacies, in the sixteenth century, the Mughal emperors used relays of horsemen to bring ice from the Hindu Kush to Delhi, where it was used in fruit sorbets. When Italian duchess Catherine de Medici married the Duke of Orléans in 1533, there is no historical evidence to support these legends, which first appeared during the 19th century. The first recipe in French for flavoured ices appears in 1674, recipes for sorbetti saw publication in the 1694 edition of Antonio Latinis Lo Scalco alla Moderna. Recipes for flavoured ices begin to appear in François Massialots Nouvelle Instruction pour les Confitures, les Liqueurs, et les Fruits, Massialots recipes result in a coarse, pebbly texture. Latini claims that the results of his recipes should have the consistency of sugar. Ice cream recipes first appeared in England in the 18th century, the recipe for ice cream was published in Mrs. Mary Ealess Receipts in London in 1718
14.
Peanut butter
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Peanut butter is a food paste or spread made from ground dry roasted peanuts. It often contains ingredients that modify the taste or texture, such as salt. Peanut butter is popular in many countries, the United States is a leading exporter of peanut butter and itself consumes $800 million of peanut butter annually. Peanut butter is served as a spread on bread, toast or crackers and it is also used in a number of confections and packaged foods, such as Reeses Peanut Butter Cups, candy bars and peanut-flavoured granola bars. Comparable preparations are made by grinding other nuts, a variety of other nut butters are also sold, such as cashew butter and almond butter. The use of peanuts dates to the Aztecs and Incas, marcellus Gilmore Edson of Montreal, Quebec was the first to patent peanut butter in 1884. He mixed sugar into the paste to harden its consistency, kellogg served peanut butter to the patients at his Battle Creek Sanitarium. As the US National Peanut Board confirms, Contrary to popular belief, january 24 is National Peanut Butter Day in the United States. The two main types of butter are crunchy and smooth. In crunchy peanut butter, some coarsely-ground peanut fragments are included to give extra texture, the peanuts in smooth peanut butter are ground uniformly, creating a creamy texture. In the US, no product labelled as peanut butter can contain artificial sweeteners, chemical preservatives, some brands of peanut butter are sold without emulsifiers that bind the peanut oils with the peanut paste, and so require stirring after separation. Most major brands of peanut butter add white sugar, but there are others that use dried cane syrup, in 2012, organic peanut butter was available. Since the market for organic peanut butter is small, there is not enough demand to support manufacturers who produce only organic peanut butter, as a result, most organic peanut butter is produced in factories that also make non-organic peanut butter. A2012 article stated that China and India are the first and second largest producers, respectively, the United States of America. is the third largest producer of peanuts and more than half of the American peanut crop goes into making peanut butter. Peanut butter is an excellent source of protein, dietary fiber, vitamin E, pantothenic acid, also high in content are the dietary minerals manganese, magnesium, phosphorus, zinc and copper. Peanut butter is a source of thiamin, iron and potassium. Both crunchy/chunky and smooth peanut butter are sources of saturated and unsaturated fats, for people with a peanut allergy, peanut butter can cause a variety of possible allergic reactions, including life-threatening anaphylaxis. This potential effect has led to banning peanut butter, among other common foods, Peanut butters flavor combines well with other flavors, such as oatmeal, cheese, cured meats, savory sauces, and various types of breads and crackers
15.
Chewing gum
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Chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of gum base, sweeteners, softeners/ plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. The cultural tradition of chewing gum seems to have developed through a convergent evolution process, each of the early precursors to chewing gum were derived from natural growths local to the region and were chewed purely out the instinctual desire to masticate. Early chewers did not necessarily desire to derive benefits from their chewable substances. Chewing gum in many forms has existed since the Neolithic period,6, 000-year-old chewing gum made from birch bark tar, with tooth imprints, has been found in Kierikki in Finland. The tar from which the gums were made is believed to have antiseptic properties and it is chemically similar to petroleum tar and is in this way different from most other early gum. The Aztecs, as the ancient Mayans before them, used chicle, forms of chewing gums were also chewed in Ancient Greece. The Ancient Greeks chewed mastic gum, made from the resin of the mastic tree, mastic gum, like birch bark tar, has antiseptic properties and is believed to have been used to maintain oral health. Both chicle and mastic are tree resins, many other cultures have chewed gum-like substances made from plants, grasses, and resins. Although chewing gum can be traced back to civilizations around the world, the American Indians chewed resin made from the sap of spruce trees. The New England settlers picked up this practice, and in 1848, John B. Curtis developed, in this way, the industrializing West, having forgotten about tree gums, rediscovered chewing gum through the First Americans. Around 1850 a gum made from wax, which is a petroleum product, was developed. To sweeten these early gums the chewer would often use of a plate of powdered sugar. William Semple filed a patent on chewing gum, patent number 98,304. The first flavored chewing gum was created in the 1860s by John Colgan, Colgan mixed with powdered sugar the aromatic flavoring tolu, a powder obtained from an extract of the balsam tree, creating small sticks of flavored chewing gum he named Taffy Tolu. Colgan also lead the way in the manufacturing and packaging of chicle-based chewing gum, derived from Manilkara chicle, chicle did not succeed as a replacement for rubber, but as a gum, which was cut into strips and marketed as Adams New York Chewing Gum in 1871. Black Jack, which is flavored with licorice, Chiclets, Chewing gum gained worldwide popularity through American GIs in WWII, who were supplied chewing gum as a ration and traded it with locals. Synthetic gums were first introduced to the U. S. after chicle no longer satisfied the needs of making chewing gum
16.
Shortening
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Shortening is any fat that is a solid at room temperature and used to make crumbly pastry and other food products. Shortening is used in pastries that should not be elastic, such as cake, although butter is solid at room temperature and is frequently used in making pastry, the term shortening seldom refers to butter, but is more closely related to margarine. Originally shortening was synonymous with lard, but with the invention of margarine by French chemist Hippolyte Mège-Mouriès in 1869, since the invention of hydrogenated vegetable oil in the early 20th century, shortening has come almost exclusively to mean hydrogenated vegetable oil. Vegetable shortening shares many properties with lard, Both are semi-solid fats with a higher point than butter. They contain less water and are less prone to splattering, making them safer for frying. Lard and shortening have a fat content compared to about 80% for butter. Cake margarines and shortenings tend to contain a few percent of monoglycerides whereas other margarines typically have less, such high ratio shortenings blend better with hydrophilic ingredients such as starches and sugar. In 1907, a German chemist, Edwin Cuno Kayser, moved to Cincinnati, Ohio and he had worked for British soap manufacturer Joseph Crosfield and Sons and was well acquainted with Normanns process, as Crosfield and Sons owned the British rights to Normanns patent. While similar to lard, vegetable shortening was much cheaper to produce, shortening also required no refrigeration, which further lowered its costs and increased its appeal in a time when refrigerators were rare. With these advantages, plus an intensive advertisement campaign by Procter & Gamble, as food production became increasingly industrialized and manufacturers sought low-cost raw materials, the use of vegetable shortening also became common in the food industry. In addition, vast US government-financed surpluses of cottonseed oil, corn oil, and soy beans also helped create a market in low-cost vegetable shortening. Crisco, owned by The J. M. Smucker Company since 2002, remains the brand of shortening in the US, nowadays consisting of a blend of partially and fully hydrogenated soybean. In Ireland and the UK, Cookeen is a brand, while in Australia, Copha is popular. A short dough is one that is crumbly or mealy, the opposite of a short dough is a long dough or dough that stretches. Vegetable shortening can produce both types of dough, the difference is in technique, for a long dough, the shortening is cut in only until the pea-sized crumbs are formed, or even larger lumps may be included. After cutting in the fat, the liquid is added and the dough is shaped for baking, neither short dough nor long flake dough is considered to be creamed or stirred batters. Consequently, a low trans fat variant of Crisco was introduced in 2004, in 2006, Cookeen was also reformulated to remove trans fats. William Shurtleff and Akiko Aoyagi,2007
17.
Margarine
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Margarine is an imitation butter spread used for spreading, baking, and cooking. Hippolyte Mège-Mouriès created it in France, in 1869 and he was responding to a challenge by Emperor Napoleon III to create a butter substitute for the armed forces and lower classes. Whereas butter is made from the butterfat of milk, modern margarine is made mainly of refined oil and water. In some places in the United States it is referred to as oleo. Margarine, like butter, consists of an emulsion, with tiny droplets of water dispersed uniformly throughout a fat phase in a stable crystalline form. In some jurisdictions margarine must have a fat content of 80% to be labelled as such. Colloquially in the United States, the term margarine is used to describe non-dairy spreads like Country Crock, Margarine can be used for spreading, baking, and cooking. It is also used as an ingredient in other food products, such as pastries, doughnuts and cookies. Margarine originated with the discovery by French chemist Michel Eugène Chevreul in 1813 of margaric acid, scientists at the time regarded margaric acid, like oleic acid and stearic acid, as one of the three fatty acids that, in combination, form most animal fats. In 1853, the German structural chemist Wilhelm Heinrich Heintz analyzed margaric acid as simply a combination of stearic acid, Emperor Napoleon III of France offered a prize to anyone who could make a satisfactory butter alternative, suitable for use by the armed forces and the lower classes. French chemist Hippolyte Mège-Mouriès invented a substance he called oleomargarine, which shortened to the trade name margarine. Mège-Mouriès patented the concept in 1869 and expanded his initial manufacturing operation from France but had commercial success. In 1871, he sold the patent to the Dutch company Jurgens, in the same year a German pharmacist, Benedict Klein from Cologne, founded the first margarine factory Benedict Klein Margarinewerke, producing the brands Overstolz and Botteram. In John Steeles 1850 California gold miners journal, he wrote, I became acquainted with Mr. Dainels, from Baltimore, manufactured butter from tallow and lard, and it looked and tasted so much like real butter, that. I could not tell the difference, however, he deceived no one, but sold it for just what it was. He never explained the process of its manufacturer, and whether he was the originator of oleomargarine I do not know, the principal raw material in the original formulation of margarine was beef fat. In 1871, Henry W. Bradley of Binghamton, New York received U. S, patent 110,626 for a process of creating margarine that combined vegetable oils with animal fats. The depression of the 1930s, followed by the rationing of World War II, led to a reduction in supply of animal fat, while butter that cows produced had a slightly yellow color, margarine had a white color, making the margarine look more like lard
18.
Pringles
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Pringles is a brand of potato and wheat-based stackable snack chips owned by Kelloggs. The snack was developed by Procter & Gamble, who first sold the product in 1967. P&G sold the brand to Kelloggs in 2012, Pringles were initially sold in 1967 and became nationally distributed across the US in 1975, and internationally from 1991 onwards. P&G wanted to create a perfect chip to address complaints about broken, greasy. The task was assigned to chemist Fredric Baur, who, from 1956 to 1958, created Pringles’ saddle shape from fried dough, Baur could not figure out how to make the chips taste good and he eventually was pulled off the Pringles job to work on another brand. In the mid-1960s, another P&G researcher, Alexander Liepa of Montgomery, Ohio, restarted Baur’s work, and set out to improve on the Pringles taste, while Baur was the true inventor of the Pringles chip, Liepas name is on the patent. Gene Wolfe, a mechanical engineer-author known for science fiction and fantasy novels and their consistent saddle shape is mathematically known as a hyperbolic paraboloid. Their designers reportedly used supercomputers to ensure that the chips aerodynamics would keep them in place during packaging, there are several theories behind the origin of the name Pringles. One theory refers to Mark Pringle, who filed a US Patent 2,286,644 titled Method, Pringles work was cited by Procter & Gamble in filing their own patent for improving the taste of dehydrated processed potatoes. Another theory suggested two Procter advertising employees lived on Pringle Drive in Finneytown, and the name paired well with potato, another theory says that P&G chose the Pringles name from a Cincinnati telephone book. They were originally known as Pringles Newfangled Potato Chips, but other snack manufacturers objected, faced with such an unpalatable appellation, Pringles eventually opted to rename their product potato crisps instead of chips. This later led to issues in the United Kingdom, where the term potato crisps refers to the product Americans call potato chips. In April 2011, P&G agreed to the $2.35 billion sale of the brand to Diamond Foods of California, however, the deal fell through in February 2012 after a year-long delay due to issues over Diamonds accounts. On 31 May 2012, Kellogg Company officially acquired Pringles for $2.695 billion as part of a plan to grow its international snacks business, the acquisition of Pringles makes Kellogg the second-largest savory snacks company in the world. Pringles are manufactured in factories in Jackson, Tennessee, Mechelen, Belgium, Johor, Malaysia, Kutno, Poland, Fujian, Pringles have about 42% potato content, the remainder being wheat starch and flours combined with vegetable oils, an emulsifier, salt, and seasoning. Pringles varieties vary in their ingredients, in July 2008 in the London High Court, P&G lawyers successfully argued that Pringles were not crisps as the potato content was only 42% and their shape, P&G stated, is not found in nature. This ruling, against a United Kingdom VAT and Duties Tribunal decision to the contrary, exempted Pringles from the then 17. 5% VAT for potato crisps, in May 2009, the Court of Appeal reversed the earlier decision. A spokesman for P&G stated it had been paying the VAT proactively, standard flavors include original, salt and vinegar, sour cream and onion, cheddar cheese, ranch dressing, barbecue, hot and spicy, and loaded baked potato
19.
Second messenger system
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Second messengers are intracellular signaling molecules released by the cell to trigger physiological changes such as proliferation, differentiation, migration, survival, and apoptosis. Secondary messengers are therefore one of the components of intracellular signal transduction cascades. Examples of second messenger molecules include cyclic AMP, cyclic GMP, inositol trisphosphate, diacylglycerol, the cell releases second messenger molecules in response to exposure to extracellular signaling molecules—the first messengers. First messengers are extracellular factors, often hormones or neurotransmitters, such as epinephrine, growth hormone, for example, RasGTP signals link with the Mitogen Activated Protein Kinase cascade to amplify the allosteric activation of proliferative transcription factors such as Myc and CREB. Earl Wilbur Sutherland, Jr. discovered second messengers, for which he won the 1971 Nobel Prize in Physiology or Medicine, Sutherland saw that epinephrine would stimulate the liver to convert glycogen to glucose in liver cells, but epinephrine alone would not convert glycogen to glucose. He found that epinephrine had to trigger a second messenger, cyclic AMP, the mechanisms were worked out in detail by Martin Rodbell and Alfred G. Gilman, who won the 1994 Nobel prize. These small molecules bind and activate protein kinases, ion channels and these intracellular messengers have some properties in common, They can be synthesized/released and broken down again in specific reactions by enzymes or ion channels. Some can be stored in special organelles and quickly released when needed and their production/release and destruction can be localized, enabling the cell to limit space and time of signal activity. There are several different secondary messenger systems, but they all are similar in overall mechanism, although the substances involved. In most cases, a ligand binds to a receptor protein molecule. The binding of a ligand to the causes an conformation change in the receptor. This conformation change can affect the activity of the receptor and result in the production of active second messages, in the case of G protein-coupled receptors, the conformation change exposes a binding site for a G-protein. The G-protein is bound to the membrane of the cell. The G-protein is known as the transducer, when the G-protein binds with the receptor, it becomes able to exchange a GDP molecule on its alpha subunit for a GTP molecule. Once this exchange takes place, the subunit of the G-protein transducer breaks free from the beta and gamma subunits. The alpha subunit, now free to move along the inner membrane, the primary effector then has an action, which creates a signal that can diffuse within the cell. This signal is called the second messenger, the secondary messenger may then activate a secondary effector whose effects depend on the particular secondary messenger system. Calcium ions are one type of second messengers and are responsible for many important physiological functions including muscle contraction, fertilization, the ions are normally bound or stored in intracellular components and can be released during signal transduction
20.
Lipid signaling
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As such, many lipid signaling molecules cannot circulate freely in solution but, rather, exist bound to special carrier proteins in serum. Ceramide can be generated by the breakdown of sphingomyelin by sphingomyelinases, being located in the metabolic hub, ceramide leads to the formation of other sphingolipids, with the C1 hydroxyl group as the major site of modification. A sugar can be attached to ceramide through the action of the enzymes, ceramide can also be broken down by enzymes called ceramidases, leading to the formation of sphingosine, Moreover, a phosphate group can be attached to ceramide by the enzyme, ceramide kinase. It is also possible to regenerate sphingomyelin from ceramide by accepting a phosphocholine headgroup from phosphatidylcholine by the action of an enzyme called sphingomyelin synthase, the latter process results in the formation of diacylglycerol from PC. Ceramide contains two hydrophobic chains and a neutral headgroup, consequently, it has limited solubility in water and is restricted within the organelle where it was formed. Also, because of its nature, ceramide readily flip-flops across membranes as supported by studies in membrane models. However, ceramide can possibly interact with lipids to form bigger regions called microdomains which restrict its flip-flopping abilities. Ceramide mediates many cell-stress responses, including the regulation of programmed cell death, numerous research works have focused interest on defining the direct protein targets of action of ceramide. The same results were found for certain inducers of apoptosis particularly stimulators of receptors in a class of lymphocytes called B-cells, regulation of the de novo synthesis of ceramide by palmitate may have a key role in diabetes and the metabolic syndrome. Experimental evidence shows there is substantial increase of ceramide levels upon adding palmitate. Ceramide accumulation activates PP2A and the subsequent dephosphorylation and inactivation of AKT and this results in a substantial decrease in insulin responsiveness and in the death of insulin-producing cells in the pancreas called islets of Langerhans. Inhibition of ceramide synthesis in mice via drug treatments or gene-knockout techniques prevented insulin resistance induced by fatty acids, glucocorticoids or obesity, in some studies, SMase activation results to its transport to the plasma membrane and the simultaneous formation of ceramide. Ceramide transfer protein transports ceramide from ER to the Golgi for the synthesis of SM, up to date, there are at least 26 distinct enzymes with varied subcellular localizations, that act on ceramide as either a substrate or product. Regulation of ceramide levels can therefore be performed by one of these enzymes in distinct organelles by particular mechanisms at various times, sphingosine is formed by the action of ceramidase enzymes on ceramide in the lysosome. Sph can also be formed in the side of the plasma membrane by the action of neutral CDase enzyme. Sph then is either recycled back to ceramide or phosphorylated by one of the kinase enzymes, SK1. The product sphingosine-1-phosphate can be dephosphorylated in the ER to regenerate sphingosine by certain S1P phosphatase enzymes within cells, sphingosine is a single-chain lipid, rendering it to have sufficient solubility in water. This explains its ability to move between membranes and to flip-flop across a membrane, estimates conducted at physiological pH show that approximately 70% of sphingosine remains in membranes while the remaining 30% is water-soluble
21.
Hydrolysis
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Hydrolysis usually means the cleavage of chemical bonds by the addition of water. When a carbohydrate is broken into its component sugar molecules by hydrolysis, generally, hydrolysis or saccharification is a step in the degradation of a substance. Hydrolysis can be the reverse of a reaction in which two molecules join together into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water, usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both substance and water molecule to split into two parts, in such reactions, one fragment of the target molecule gains a hydrogen ion. A common kind of hydrolysis occurs when a salt of an acid or weak base is dissolved in water. Water spontaneously ionizes into hydroxide anions and hydronium cations, the salt also dissociates into its constituent anions and cations. For example, sodium acetate dissociates in water into sodium and acetate ions, sodium ions react very little with the hydroxide ions whereas the acetate ions combine with hydronium ions to produce acetic acid. In this case the net result is an excess of hydroxide ions. For example, dissolving sulfuric acid in water is accompanied by hydrolysis to give hydronium and bisulfate, for a more technical discussion of what occurs during such a hydrolysis, see Brønsted–Lowry acid–base theory. Acid–base-catalysed hydrolyses are very common, one example is the hydrolysis of amides or esters and their hydrolysis occurs when the nucleophile attacks the carbon of the carbonyl group of the ester or amide. In an aqueous base, hydroxyl ions are better nucleophiles than polar molecules such as water, in acids, the carbonyl group becomes protonated, and this leads to a much easier nucleophilic attack. The products for both hydrolyses are compounds with carboxylic acid groups, perhaps the oldest commercially practiced example of ester hydrolysis is saponification. It is the hydrolysis of a triglyceride with a base such as sodium hydroxide. During the process, glycerol is formed, and the fatty acids react with the base and these salts are called soaps, commonly used in households. In addition, in living systems, most biochemical reactions take place during the catalysis of enzymes, the catalytic action of enzymes allows the hydrolysis of proteins, fats, oils, and carbohydrates. As an example, one may consider proteases and they catalyse the hydrolysis of interior peptide bonds in peptide chains, as opposed to exopeptidases. However, proteases do not catalyse the hydrolysis of all kinds of proteins and their action is stereo-selective, Only proteins with a certain tertiary structure are targeted as some kind of orienting force is needed to place the amide group in the proper position for catalysis
22.
Phosphatidylinositol 4,5-bisphosphate
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Phosphatidylinositol 4, 5-bisphosphate or PtdInsP2, also known simply as PIP2, is a minor phospholipid component of cell membranes. PtdInsP2 is enriched at the membrane where it is a substrate for a number of important signaling proteins. PtdInsP2 is formed primarily by the type I phosphatidylinositol 4-phosphate 5-kinases from PIP, in metazoans, PtdInsP2 can also be formed by type II phosphatidylinositol 5-phosphate 4-kinases from PIP. The fatty acids of PtdInsP2 are variable in different species and tissues, PtdInsP2 regulates the organization, polymerization, and branching of filamentous actin via direct binding to F-actin regulatory proteins. PtdInsP2 recruits cytosolic septin monomers/oligomers to membrane surfaces via direct binding to the motif present in septin monomers. PtdInsP2 is a substrate for hydrolysis by phospholipase C, a membrane-bound enzyme activated through protein receptors such as α1 adrenergic receptors, PtdInsP2 regulates the function of many membrane proteins and ion channels, such as the M-channel. The products of the PLC catalyzation of PtdInsP2 are inositol 1,4, 5-trisphosphate and diacylglycerol, in this cascade, DAG remains on the cell membrane and activates the signal cascade by activating protein kinase C. PKC in turn activates other proteins by phosphorylating them. The effect of PKC could be reversed by phosphatases, calcium participates in the cascade by activating other proteins. Class I PI 3-kinases phosphorylate PtdInsP2 forming phosphatidylinositol -trisphosphate, examples of proteins activated by PtdInsP3 are AKT, PDPK1, Btk1. One mechanism for direct effect of PtdInsP2 is opening of Na+ channels as a function in growth hormone release by growth hormone-releasing hormone. Inwardly rectifying potassium channels have been shown to require docking of PtdInsP2 for channel activity, PtdInsP2 is regulated by many different components. One emerging hypothesis is that PtdInsP2 concentration is maintained locally
23.
Enzyme
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Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions, the molecules at the beginning of the process upon which enzymes may act are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. The study of enzymes is called enzymology, enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins, although a few are catalytic RNA molecules, enzymes specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy, some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example is orotidine 5-phosphate decarboxylase, which allows a reaction that would take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules, inhibitors are molecules that decrease enzyme activity, many drugs and poisons are enzyme inhibitors. An enzymes activity decreases markedly outside its optimal temperature and pH, some enzymes are used commercially, for example, in the synthesis of antibiotics. French chemist Anselme Payen was the first to discover an enzyme, diastase and he wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells. In 1877, German physiologist Wilhelm Kühne first used the term enzyme, the word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment was used to refer to chemical activity produced by living organisms. Eduard Buchner submitted his first paper on the study of yeast extracts in 1897, in a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts even when there were no living yeast cells in the mixture. He named the enzyme that brought about the fermentation of sucrose zymase, in 1907, he received the Nobel Prize in Chemistry for his discovery of cell-free fermentation. Following Buchners example, enzymes are usually named according to the reaction they carry out, the biochemical identity of enzymes was still unknown in the early 1900s. Sumner showed that the enzyme urease was a protein and crystallized it. These three scientists were awarded the 1946 Nobel Prize in Chemistry, the discovery that enzymes could be crystallized eventually allowed their structures to be solved by x-ray crystallography. This high-resolution structure of lysozyme marked the beginning of the field of structural biology, an enzymes name is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase
24.
Phospholipase C
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Phospholipase C is a class of membrane-associated enzymes that cleave phospholipids just before the phosphate group. It is most commonly taken to be synonymous with the forms of this enzyme. There are thirteen kinds of mammalian phospholipase C that are classified into six isotypes according to structure, each PLC has unique and overlapping controls over expression and subcellular distribution. Activators of each PLC vary, but typically include heterotrimeric G protein subunits, protein kinases, small G proteins, Ca2+. The extensive number of functions exerted by the PLC reaction requires that it be strictly regulated and able to respond to multiple extra- and this need has guided the evolution of six isotypes of PLC in animals, each with a distinct mode of regulation. The pre-mRNA of PLC can also be subject to differential splicing such that a mammal may have up to 30 PLC enzymes, the toxic phospholipases C are capable of interacting with eukaryotic cell membranes and hydrolyzing phosphatidylcholine and sphingomyelin, ultimately leading to cell lysis. The core enzyme includes a split triosephosphate isomerase barrel, pleckstrin homology domain, four tandem EF hand domains, the TIM barrel contains the active site, all catalytic residues, and a Ca2+ binding site. It has an insert that interrupts its activity called an X-Y linker. The X-Y linker has been shown to occlude the active site, the genes encoding alpha-toxin, Bacillus cereus PLC, and PLCs from Clostridium bifermentans and Listeria monocytogenes have been isolated and nucleotides sequenced. There is significant homology of the sequences, approximately 250 residues, alpha-toxin has an additional 120 residues in the C-terminus. The primary catalyzed reaction of PLC occurs on a substrate at a lipid-water interface. The residues in the site are conserved in all PLC isotypes. In animals, PLC selectively catalyzes the hydrolysis of the phospholipid, phosphatidylinositol 4, 5-bisphosphate, there is the formation of a weakly enzyme-bound intermediate, inositol 1, 2-cyclic phosphodiester, and release of diacyl glycerol. The intermediate is then hydrolyzed to inositol 1,4, 5-trisphosphate, thus the two end products are DAG and IP3. The acid/base catalysis requires two conserved residues and a Ca2+ ion is needed for PIP2 hydrolysis. It has been observed that the active-site Ca2+ coordinates with four acidic residues, activators of this pathway include PDGF and FGF. βγ-complex of heterotrimeric G-proteins, as in a pathway of growth hormone release by growth hormone-releasing hormone. Small molecule U73122, aminosteroid, putative PLC inhibitor, however, the specificity of U73122 has been questioned
25.
Cell membrane
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The cell membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is permeable to ions and organic molecules and controls the movement of substances in. The basic function of the membrane is to protect the cell from its surroundings. It consists of the bilayer with embedded proteins. Cell membranes can be artificially reassembled, Some authors that did not believe that there was a functional permeable boundary at the surface of the cell preferred to use the term plasmalemma to the extern region of the cell. The cell membrane surrounds the cytoplasm of living cells, physically separating the components from the extracellular environment. The cell membrane also plays a role in anchoring the cytoskeleton to provide shape to the cell, fungi, bacteria, most archaea, and plants also have a cell wall, which provides a mechanical support to the cell and precludes the passage of larger molecules. The cell membrane is permeable and able to regulate what enters and exits the cell. The movement of substances across the membrane can be passive, occurring without the input of cellular energy, or active. The membrane also maintains the cell potential, the cell membrane thus works as a selective filter that allows only certain things to come inside or go outside the cell. The cell employs a number of mechanisms that involve biological membranes,1. Passive osmosis and diffusion, Some substances such as carbon dioxide and oxygen, can move across the membrane by diffusion. Because the membrane acts as a barrier for certain molecules and ions, such a concentration gradient across a semipermeable membrane sets up an osmotic flow for the water. Transmembrane protein channels and transporters, Nutrients, such as sugars or amino acids, must enter the cell, such molecules diffuse passively through protein channels such as aquaporins in facilitated diffusion or are pumped across the membrane by transmembrane transporters. Protein channel proteins, also called permeases, are quite specific, recognizing and transporting only a limited food group of chemical substances. Endocytosis, Endocytosis is the process in which cells absorb molecules by engulfing them, the plasma membrane creates a small deformation inward, called an invagination, in which the substance to be transported is captured. The deformation then pinches off from the membrane on the inside of the cell, Endocytosis is a pathway for internalizing solid particles, small molecules and ions, and macromolecules. Endocytosis requires energy and is thus a form of active transport and this is the process of exocytosis
26.
Inositol trisphosphate
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Inositol trisphosphate or inositol 1,4, 5-trisphosphate, together with diacylglycerol, is a secondary messenger molecule used in signal transduction and lipid signaling in biological cells. While DAG stays inside the membrane, IP3 is soluble and diffuses through the cell and it is made by hydrolysis of phosphatidylinositol 4, 5-bisphosphate, a phospholipid that is located in the plasma membrane, by phospholipase C. IP3 is a molecule with a molecular mass of 420.10 g/mol. It is composed of a ring with three phosphate groups bound at the 1,4, and 5 carbon positions, and three hydroxyl groups bound at positions 2,3, and 6. Phosphate groups can exist in three different forms depending on a solutions pH, phosphorus atoms can bind three oxygen atoms with single bonds and a fourth oxygen atom using a double/dative bond. The pH of the solution, and thus the form of the phosphate group determines its ability to bind to other molecules, the binding of phosphate groups to the inositol ring is accomplished by phosphor-ester binding. This bond involves combining a group from the inositol ring. Considering that the average physiological pH is approximately 7.4 and this gives IP3 a net negative charge, which is important in allowing it to dock to its receptor, through binding of the phosphate groups to positively charged residues on the receptor. IP3 has three hydrogen bond donors in the form of its three hydroxyl groups, the hydroxyl group on the 6th carbon atom in the inositol ring is also involved in IP3 docking. The docking of IP3 to its receptor, which is called the inositol trisphosphate receptor, was first studied using deletion mutagenesis in the early 1990s, studies focused on the N-terminus side of the IP3 receptor. In 1997 researchers localized the region of the IP3 receptor involved with binding of IP3 to between amino acid residues 226 and 578 in 1997, considering that IP3 is a negatively charged molecule, positively charged amino acids such as arginine and lysine were believed to be involved. Two arginine residues at position 265 and 511 and one lysine residue at position 508 were found to be key in IP3 docking, using a modified form of IP3, it was discovered that all three phosphate groups interact with the receptor, but not equally. Phosphates at the 4th and 5th positions interact more extensively than the phosphate at the 1st position, up until then phospholipids were believed to be innate structures only used by cells as building blocks for construction of the plasma membrane. He hypothesized that receptor-activated hydrolysis of PIP2 produced a molecule that caused increases in intracellular calcium mobilization and this idea was researched extensively by Michell and his colleagues, who in 1981 were able to show that PIP2 is hydrolyzed into DAG and IP3 by a then unknown phosphodiesterase. It was discovered in 1989 that phospholipase C is the responsible for hydrolyzing PIP2 into DAG. Today the IP3 signaling pathway is mapped out, and is known to be important in regulating a variety of calcium-dependent cell signaling pathways. Increases in the intracellular Ca2+ concentrations are often a result of IP3 activation and this occurs in cells that are capable of responding to growth factors such as insulin, because the growth factors are the ligands responsible for activating the RTK. IP3 is a molecule and is capable of diffusing through the cytoplasm to the ER, or the sarcoplasmic reticulum in the case of muscle cells
27.
Cytosol
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The cytosol or cytoplasmic matrix is the liquid found inside cells. It constitutes most of the intracellular fluid and it is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into many compartments, in the eukaryotic cell, the cytosol is within the cell membrane and is part of the cytoplasm, which also comprises the mitochondria, plastids, and other organelles, the cell nucleus is separate. The cytosol is thus a liquid matrix around the organelles, in prokaryotes, most of the chemical reactions of metabolism take place in the cytosol, while a few take place in membranes or in the periplasmic space. In eukaryotes, while many metabolic pathways occur in the cytosol. The cytosol is a mixture of substances dissolved in water. Although water forms the majority of the cytosol, its structure. The cytosol also contains amounts of macromolecules, which can alter how molecules behave. Although it was thought to be a simple solution of molecules. Such a soluble cell extract is not identical to the part of the cell cytoplasm and is usually called a cytoplasmic fraction. The term cytosol is now used to refer to the phase of the cytoplasm in an intact cell. This excludes any part of the cytoplasm that is contained within organelles, prior to this, other terms were used for the cell fluid, not always synonymously, as its nature was not very clear. The cytosol consists mostly of water, dissolved ions, small molecules, the majority of these non-protein molecules have a molecular mass of less than 300 Da. This mixture of molecules is extraordinarily complex, as the variety of molecules that are involved in metabolism is immense. For example, up to 200,000 different small molecules might be made in plants, although not all these will be present in the same species, or in a single cell. Estimates of the number of metabolites in single cells such as E. coli, most of the cytosol is water, which makes up about 70% of the total volume of a typical cell. The pH of the fluid is 7.4. While human cytosolic pH ranges between 7.0 -7.4, and is higher if a cell is growing
28.
Hydrophobe
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In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water. In contrast, hydrophiles are attracted to water, Hydrophobic molecules tend to be nonpolar and, thus, prefer other neutral molecules and nonpolar solvents. Because water molecules are polar, hydrophobes do not dissolve well among them, Hydrophobic molecules in water often cluster together, forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle, examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, Hydrophobic is often used interchangeably with lipophilic, fat-loving. However, the two terms are not synonymous, while hydrophobic substances are usually lipophilic, there are exceptions—such as the silicones and fluorocarbons. The term hydrophobe comes from the Ancient Greek ὑδρόφοβος, having a horror of water, constructed from ὕδωρ, water, thus, the two immiscible phases will change so that their corresponding interfacial area will be minimal. This effect can be visualized in the phenomenon called phase separation, Superhydrophobic surfaces, such as the leaves of the lotus plant, are those that are extremely difficult to wet. The contact angles of a water droplet exceeds 150° and the angle is less than 10°. This is referred to as the Lotus effect, and is primarily a physical property related to interfacial tension, in 1805, Thomas Young defined the contact angle θ by analyzing the forces acting on a fluid droplet resting on a solid surface surrounded by a gas. Wenzels equation shows that microstructuring a surface amplifies the natural tendency of the surface, a hydrophobic surface becomes more hydrophobic when microstructured – its new contact angle becomes greater than the original. However, a hydrophilic surface becomes more hydrophilic when microstructured – its new contact angle less than the original. Liquid in the Cassie–Baxter state is more mobile than in the Wenzel state and we can predict whether the Wenzel or Cassie–Baxter state should exist by calculating the new contact angle with both equations. By a minimization of free energy argument, the relation that predicted the new contact angle is the state most likely to exist. Stated in mathematical terms, for the Cassie–Baxter state to exist, a new criterion for the switch between Wenzel and Cassie-Baxter states has been developed recently based on surface roughness and surface energy. Contact angle is a measure of static hydrophobicity, and contact angle hysteresis, contact angle hysteresis is a phenomenon that characterizes surface heterogeneity. When a pipette injects a liquid onto a solid, the liquid will form some contact angle, as the pipette injects more liquid, the droplet will increase in volume, the contact angle will increase, but its three-phase boundary will remain stationary until it suddenly advances outward. The contact angle the droplet had immediately before advancing outward is termed the advancing contact angle, the receding contact angle is now measured by pumping the liquid back out of the droplet
29.
Phorbol esters
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Phorbol is a natural, plant-derived organic compound. It is a member of the family of diterpenes. Phorbol was first isolated in 1934 as the product of croton oil. The structure of phorbol was determined in 1967, phorbol is identified as the active constituent of the highly toxic New World tropical manchineel or beach apple Hippomane mancinella. It is very soluble in most polar solvents, as well as in water. In the manchineel, this leads to an exposure risk during rain. Various esters of phorbol have important biological properties, the most notable of which is the capacity to act as tumor promoters through activation of protein kinase C and they mimic diacylglycerols, glycerol derivatives in which two hydroxyl groups have reacted with fatty acids to form esters. The most common phorbol ester is 12-O-tetradecanoylphorbol-13-acetate, also called phorbol-12-myristate-13-acetate, PMA, together with ionomycin, can also be used to stimulate T-cell activation, proliferation, and cytokine production, and is used in protocols for intracellular staining of these cytokines. The total synthesis of phorbol has been reported, phorbols at the US National Library of Medicine Medical Subject Headings
30.
Cell (biology)
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The cell is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, the study of cells is called cell biology. Cells consist of cytoplasm enclosed within a membrane, which contains many such as proteins. Organisms can be classified as unicellular or multicellular, while the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion cells. Most plant and animal cells are only under a microscope. The cell was discovered by Robert Hooke in 1665, who named the unit for its resemblance to cells inhabited by Christian monks in a monastery. Cells emerged on Earth at least 3.5 billion years ago, Cells are of two types, eukaryotic, which contain a nucleus, and prokaryotic, which do not. Prokaryotes are single-celled organisms, while eukaryotes can be either single-celled or multicellular, prokaryotic cells were the first form of life on Earth, characterised by having vital biological processes including cell signaling and being self-sustaining. They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus, prokaryotes include two of the domains of life, bacteria and archaea. The DNA of a prokaryotic cell consists of a chromosome that is in direct contact with the cytoplasm. The nuclear region in the cytoplasm is called the nucleoid, most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 µm in diameter. Though most prokaryotes have both a cell membrane and a wall, there are exceptions such as Mycoplasma and Thermoplasma which only possess the cell membrane layer. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, the cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and bursting from osmotic pressure due to a hypotonic environment, some eukaryotic cells also have a cell wall. Inside the cell is the region that contains the genome, ribosomes. The genetic material is found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular, linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease. Though not forming a nucleus, the DNA is condensed in a nucleoid, plasmids encode additional genes, such as antibiotic resistance genes
31.
Prostaglandin
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The prostaglandins are a group of physiologically active lipid compounds having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals and they are derived enzymatically from fatty acids. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring and they are a subclass of eicosanoids and of the prostanoid class of fatty acid derivatives. The structural differences between prostaglandins account for their different biological activities, a given prostaglandin may have different and even opposite effects in different tissues in some cases. The ability of the same prostaglandin to stimulate a reaction in one tissue and they act as autocrine or paracrine factors with their target cells present in the immediate vicinity of the site of their secretion. Prostaglandins differ from endocrine hormones in that they are not produced at a specific site, prostaglandins are powerful locally acting vasodilators and inhibit the aggregation of blood platelets. Through their role in vasodilation, prostaglandins are also involved in inflammation and they are synthesized in the walls of blood vessels and serve the physiological function of preventing needless clot formation, as well as regulating the contraction of smooth muscle tissue. Conversely, thromboxanes are vasoconstrictors and facilitate platelet aggregation and their name comes from their role in clot formation. Specific prostaglandins are named with a letter followed by a number, for example, prostaglandin E1 is abbreviated PGE1 or PGE1, and prostaglandin I2 is abbreviated PGI2 or PGI2. The name prostaglandin derives from the prostate gland, when prostaglandin was first isolated from seminal fluid in 1935 by the Swedish physiologist Ulf von Euler, and independently by M. W. Goldblatt, it was believed to be part of the prostatic secretions, in fact, prostaglandins are produced by the seminal vesicles. It was later shown that many other tissues secrete prostaglandins for various functions, the first total syntheses of prostaglandin F2α and prostaglandin E2 were reported by E. J. Corey in 1969, an achievement for which he was awarded the Japan Prize in 1989. In 1971, it was determined that aspirin-like drugs could inhibit the synthesis of prostaglandins, the biochemists Sune K. Bergström, Bengt I. Samuelsson and John R. Vane jointly received the 1982 Nobel Prize in Physiology or Medicine for their research on prostaglandins, prostaglandins are found in most tissues and organs. They are produced by almost all nucleated cells and they are autocrine and paracrine lipid mediators that act upon platelets, endothelium, uterine and mast cells. They are synthesized in the cell from the fatty acids. An intermediate arachidonic acid is created from diacylglycerol via phospholipase-A2, then brought to either the cyclooxygenase pathway or the lipoxygenase pathway, prostaglandins were originally believed to leave the cells via passive diffusion because of their high lipophilicity. The release of prostaglandin has now also shown to be mediated by a specific transporter, namely the multidrug resistance protein 4
32.
Endocannabinoid
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Two primary endocannabinoid receptors have been identified, CB1, first cloned in 1990, and CB2, cloned in 1993. One other main endocannabinoid is 2-Arachidonoylglycerol which is active at both cannabinoid receptors, along with its own mimetic phytocannabinoid, CBD, 2-AG and CBD are involved in the regulation of appetite, immune system functions and pain management. The enzymes that synthesize and degrade the endocannabinoids, such as fatty acid amide hydrolase or monoacylglycerol lipase, the cannabinoid receptors CB1 and CB2, two G protein-coupled receptors that are located in the central and peripheral nervous systems. The neurons, neural pathways, and other cells where these molecules, enzymes, the endocannabinoid system has been studied using genetic and pharmacological methods. These studies have revealed that cannabinoids act as neuromodulators for a variety of processes, including motor learning, appetite, Cannabinoid binding sites exist throughout the central and peripheral nervous systems. The two most relevant receptors for cannabinoids are the CB1 and CB2 receptors, which are expressed predominantly in the brain, density of expression varies based on species and correlates with the efficacy that cannabinoids will have in modulating specific aspects of behavior related to the site of expression. For example, in rodents, the highest concentration of cannabinoid binding sites are in the ganglia and cerebellum. Binding has been demonstrated by 2-arachidonoylglycerol on the TRPV1 receptor suggesting that this receptor may be a candidate for the established response, in addition to CB1 and CB2, certain orphan receptors are known to bind endocannabinoids as well, including GPR18, GPR55, and GPR119. During neurotransmission, the pre-synaptic neuron releases neurotransmitters into the cleft which bind to cognate receptors expressed on the post-synaptic neuron. Expression appears to be exclusive, so both types of endocannabinoids are not co-synthesized. Evidence suggests that the influx of calcium into the post-synaptic neuron causes the activation of an enzyme called transacylase. This enzyme is suggested to catalyze the first step of endocannabinoid biosynthesis by converting phosphatidylethanolamine, experiments have shown that phospholipase D cleaves NAPE to yield anandamide. This process is mediated by bile acids, in NAPE-phospholipase D -knockout mice, cleavage of NAPE is reduced in low calcium concentrations, but not abolished, suggesting multiple, distinct pathways are involved in anandamide synthesis. The synthesis of 2-AG is less established and warrants further research, once released into the extracellular space by a putative endocannabinoid transporter, messengers are vulnerable to glial cell inactivation. While arachidonic acid is a substrate for leukotriene and prostaglandin synthesis, a neuropharmacological study demonstrated that an inhibitor of FAAH selectively increases anandamide levels in the brain of rodents and primates. Such approaches could lead to the development of new drugs with analgesic, anxiolytic-like and antidepressant-like effects, Cannabinoid receptors are G-protein coupled receptors located on the pre-synaptic membrane. The relative potency of different cannabinoids in inhibition of adenylyl cyclase correlates with their varying efficacy in behavioral assays and this inhibition of cAMP is followed by phosphorylation and subsequent activation of not only a suite of MAP kinases, but also the PI3/PKB and MEK/ERK pathway. In addition, CB1 activation has been demonstrated to increase the activity of transcription factors like c-Fos, the molecular mechanisms of CB1-mediated changes to the membrane voltage have also been studied in detail
33.
2-Arachidonoylglycerol
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2-Arachidonoylglycerol is an endocannabinoid, an endogenous agonist of the CB1 receptor. It is a formed from the omega-6 fatty acid arachidonic acid. It is present at high levels in the central nervous system. It has been found in bovine and human milk. The chemical was first described in 1994-1995, although it had discovered some time before that. The activities of Phospholipase C and diacylglycerol lipase mediate its formation, 2-AG is synthesized from arachidonic acid-containing diacylglycerol. 2-AG, unlike anandamide, is present at high levels in the central nervous system, it is the most abundant molecular species of monoacylglycerol found in mouse. Detection of 2-AG in brain tissue is complicated by the ease of its isomerization to 1-AG during standard lipid extraction conditions. It has been found in maternal bovine as well as human milk, shimon Ben-Shabat, of Ben-Gurion University, discovered the chemical. 2-AG was a chemical compound but its occurrence in mammals. 2-Arachidonoylglycerol, next with Anandamide, was the second endocannabinoid discovered, the cannabinoid established the existence of a cannabinoid neuromodulatory system in the nervous system. Unlike anandamide, formation of 2-AG is calcium-dependent and is mediated by the activities of phospholipase C, 2-AG acts as a full agonist at the CB1 receptor. At a concentration of 0. 3nM, 2-AG induces a rapid, 2-AG is hydrolyzed in vitro by monoacylglycerol lipase, fatty acid amide hydrolase, and the uncharacterized serine hydrolase enzymes ABHD6 and ABHD12. The exact contribution of each of these enzymes to the termination of 2-AG signaling in vivo is unknown, there have been identified transport proteins for 2-arachidonoylglycerol and anandamide. These include the heat shock proteins and fatty acid binding proteins, 2-Arachidonoylglycerol is synthesized from arachidonic acid-containing diacylglycerol, which is derived from the increase of inositol phospholipid metabolism by the action of diacylglycerol lipase. 2-Arachidonoyl glyceryl ether Endocannabinoid transporters Dinh TP, Carpenter D, Leslie FM, brain monoglyceride lipase participating in endocannabinoid inactivation. Proceedings of the National Academy of Sciences of the United States of America
34.
Dihydroxyacetone phosphate
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Dihydroxyacetone phosphate is a biochemical compound involved in many metabolic pathways, including the Calvin cycle in plants and glycolysis. Dihydroxyacetone phosphate lies in the metabolic pathway, and is one of the two products of breakdown of fructose 1, 6-bisphosphate, along with glyceraldehyde 3-phosphate. It is rapidly and reversibly isomerised to glyceraldehyde 3-phosphate, Compound C05378 at KEGG Pathway Database. Enzyme 4.1.2.13 at KEGG Pathway Database, Compound C00111 at KEGG Pathway Database. Compound C00118 at KEGG Pathway Database, the numbering of the carbon atoms indicates the fate of the carbons according to their position in fructose 6-phosphate. Compound C00111 at KEGG Pathway Database. Enzyme 5.3.1.1 at KEGG Pathway Database. Compound C00118 at KEGG Pathway Database, click on genes, proteins and metabolites below to link to respective articles. In the Calvin cycle, DHAP is one of the products of the reduction of 1. It is also used in the synthesis of sedoheptulose 1, 7-bisphosphate and fructose 1, 6-bisphosphate, DHAP is also the product of the dehydrogenation of L-glycerol-3-phosphate, which is part of the entry of glycerol into the glycolytic pathway. Conversely, reduction of glycolysis-derived DHAP to L-glycerol-3-phosphate provides adipose cells with the glycerol backbone they require to synthesize new triglycerides. Both reactions are catalyzed by the enzyme glycerol 3-phosphate dehydrogenase with NAD+/NADH as cofactor, DHAP also has a role in the ether-lipid biosynthesis process in the protozoan parasite Leishmania mexicana
35.
Glycolysis
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Glycolysis is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+. The free energy released in this process is used to form the high-energy molecules ATP, glycolysis is a determined sequence of ten enzyme-catalyzed reactions. The intermediates provide entry points to glycolysis, for example, most monosaccharides, such as fructose and galactose, can be converted to one of these intermediates. The intermediates may also be directly useful, for example, the intermediate dihydroxyacetone phosphate is a source of the glycerol that combines with fatty acids to form fat. Glycolysis is an oxygen independent metabolic pathway, meaning that it not use molecular oxygen for any of its reactions. However the products of glycolysis are sometimes metabolized using atmospheric oxygen, when molecular oxygen is used for the metabolism of the products of glycolysis the process is usually referred to as aerobic, whereas if no oxygen is used the process is said to be anaerobic. Thus, glycolysis occurs, with variations, in all organisms. The wide occurrence of glycolysis indicates that it is one of the most ancient metabolic pathways, glycolysis could thus have originated from chemical constraints of the prebiotic world. Glycolysis occurs in most organisms in the cytosol of the cell, the most common type of glycolysis is the Embden–Meyerhof–Parnas, which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas. Glycolysis also refers to other pathways, such as the Entner–Doudoroff pathway, however, the discussion here will be limited to the Embden–Meyerhof–Parnas pathway. The overall reaction of glycolysis is, The use of symbols in this equation makes it appear unbalanced with respect to oxygen atoms, hydrogen atoms, and charges. In the cellular environment, all three groups of ADP dissociate into −O− and H+, giving ADP3−, and this ion tends to exist in an ionic bond with Mg2+. ATP behaves identically except that it has four groups, giving ATPMg2−. When these differences along with the charges on the two phosphate groups are considered together, the net charges of −4 on each side are balanced. For simple fermentations, the metabolism of one molecule of glucose to two molecules of pyruvate has a net yield of two molecules of ATP, most cells will then carry out further reactions to repay the used NAD+ and produce a final product of ethanol or lactic acid. Many bacteria use inorganic compounds as hydrogen acceptors to regenerate the NAD+, cells performing aerobic respiration synthesize much more ATP, but not as part of glycolysis. These further aerobic reactions use pyruvate and NADH + H+ from glycolysis, the pathway of glycolysis as it is known today took almost 100 years to fully discover. The combined results of many experiments were required in order to understand the pathway as a whole
36.
Acylation
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In chemistry, acylation is the process of adding an acyl group to a compound. The compound providing the group is called the acylating agent. Because they form a strong electrophile when treated with metal catalysts. Acyl halides and anhydrides of carboxylic acids are commonly used acylating agents to acylate amines to form amides or acylate alcohols to form esters. The amines and alcohols are nucleophiles, the mechanism is an acyl substitution. Succinic acid is commonly used in a specific type of acylation called succination. Oversuccination occurs when more than one succinate adds to a single compound, acylation can be used to prevent rearrangement reactions that would normally occur in alkylation. To do this an acylation reaction is performed, then the carbonyl is removed by reduction or a similar process. Protein acylation is the modification of proteins via the attachment of functional groups through acyl linkages. One prominent type is fatty acylation, the addition of fatty acids to amino acids. Protein acylation has been observed as a mechanism of biological signaling
37.
Phosphatidic acid
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Phosphatidic acids are the acid forms of phosphatidates, a part of common phospholipids, major constituents of cell membranes. Phosphatidic acids are the simplest diacyl-glycerophospholipids, phosphatidic acid consists of a glycerol backbone, with, in general, a saturated fatty acid bonded to carbon-1, an unsaturated fatty acid bonded to carbon-2, and a phosphate group bonded to carbon-3. Besides de novo synthesis, PA can be formed in three ways, By phospholipase D, via the hydrolysis of the P-O bond of phosphatidylcholine to produce PA and choline. By the phosphorylation of diacylglycerol by DAG kinase By the acylation of lysophosphatidic acid by lysoPA-acyltransferase, PA is degraded by conversion into DAG by lipid phosphate phosphohydrolases or into lyso-PA by phospholipase A. The role of PA in the cell can be divided into three categories, PA is the precursor for the biosynthesis of other lipids. The physical properties of PA influence membrane curvature, PA acts as a signaling lipid, recruiting cytosolic proteins to appropriate membranes. PA plays very important role in Phototransduction in Drosophila The first three roles are not mutually exclusive, PA is a vital cell lipid that acts as a biosynthetic precursor for the formation of all acylglycerol lipids in the cell. In mammalian and yeast cells, two different pathways are known for the de novo synthesis of PA, the glycerol 3-phosphate pathway or the dihydroxyacetone phosphate pathway. In bacteria, only the former pathway is present, and mutations that block this pathway are lethal, in mammalian and yeast cells, where the enzymes in these pathways are redundant, mutation of any one enzyme is not lethal. However, it is worth noting that in vitro, the various acyltransferases exhibit different substrate specificities with respect to the acyl-CoAs that are incorporated into PA. Different acyltransferases also have different intracellular distributions, such as the endoplasmic reticulum, the mitochondria or peroxisomes and this suggests that the various acyltransferases present in mammalian and yeast cells may be responsible for producing different pools of PA. The conversion of PA into diacylglycerol by LPPs is the commitment step for the production of phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine, in addition, DAG is also converted into CDP-DAG, which is a precursor for phosphatidylglycerol, phosphatidylinositol and phosphoinositides. PA concentrations are maintained at low levels in the cell by the activity of potent LPPs. These convert PA into DAG very rapidly and, because DAG is the precursor for so many other lipids and this means that any upregulation in PA production can be matched, over time, with a corresponding upregulation in LPPs and in DAG metabolising enzymes. PA is, therefore, essential for synthesis and cell survival, yet. PA is a phospholipid in that it has a small highly charged head group that is very close to the glycerol backbone. PA is known to play roles in both fission and fusion, and these roles may relate to the biophysical properties of PA. At sites of membrane budding or fusion, the membrane becomes or is highly curved, a major event in the budding of vesicles, such as transport carriers from the Golgi, is the creation and subsequent narrowing of the membrane neck
38.
Triglyceride
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A triglyceride is an ester derived from glycerol and three fatty acids. Triglycerides are the constituents of body fat in humans and other animals. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, there are many different types of triglyceride, with the main division between saturated and unsaturated types. Saturated fats are saturated with hydrogen – all available places where hydrogen atoms could be bonded to carbon atoms are occupied and these have a higher melting point and are more likely to be solid at room temperature. Unsaturated fats have double bonds between some of the atoms, reducing the number of places where hydrogen atoms can bond to carbon atoms. These have a melting point and are more likely to be liquid at room temperature. Triglycerides are chemically tri esters of fatty acids and glycerol. Triglycerides are formed by combining glycerol with three fatty acid molecules, organic acids have a carboxyl group. Alcohols and organic acids join to form esters, the glycerol molecule has three hydroxyl groups. Each fatty acid has a carboxyl group, the chain lengths of the fatty acids in naturally occurring triglycerides vary, but most contain 16,18, or 20 carbon atoms. Bacteria, however, possess the ability to synthesise odd- and branched-chain fatty acids, as a result, ruminant animal fat contains odd-numbered fatty acids, such as 15, due to the action of bacteria in the rumen. Many fatty acids are unsaturated, some are polyunsaturated, most natural fats contain a complex mixture of individual triglycerides. Because of this, they melt over a range of temperatures. Cocoa butter is unusual in that it is composed of only a few triglycerides, derived from palmitic, oleic, and stearic acids in the 1-, 2-, the simplest triglycerides are those where the three fatty acids are identical. Their names indicate the fatty acid, stearin derived from acid, palmitin derived from palmitic acid. These compounds can be obtained as three forms or polymorphs, α, β, and β′ and these forms differ in terms of their melting points. If the first and third chain R and R″ are different, then the carbon atom is a chiral centre. The pancreatic lipase acts at the bond, hydrolysing the bond. In triglyceride form, lipids cannot be absorbed by the duodenum, fatty acids, monoglycerides, and some diglycerides are absorbed by the duodenum, once the triglycerides have been broken down
39.
Monoglyceride
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Monoglycerides are a class of glycerides which are composed of a molecule of glycerol linked to a fatty acid via an ester bond. Monoglycerides are produced both biologically and industrially and they are naturally present at very low levels in some seed oils such as olive oil, rapeseed oil and cottonseed oil. Industrial production is achieved by a glycerolysis reaction between triglycerides and glycerol. The commercial raw materials for the production of monoacylglycerols may be vegetable or animal fats. Monoglycerides are primarily used as surfactants, usually in the form of emulsifiers, together with diglycerides, monoglycerides are commonly added to commercial food products in small quantities as E471, which helps to prevent mixtures of oils and water from separating. The values given in the labels for total fat, saturated fat. They are also found in bakery products, beverages, ice cream, chewing gum, shortening, whipped toppings, margarine. In bakery products, monoglycerides are useful in improving loaf volume and texture, diglyceride Dietary sources of fatty acids, their digestion, absorption, transport in the blood and storage Lipid Triglyceride
40.
Fatty acid metabolism
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Fatty acid metabolism consists of catabolic processes that generate energy, and anabolic processes that create biologically important molecules. Fatty acids are a family of molecules classified within the lipid macronutrient class, one role of fatty acids in animal metabolism is energy production, captured in the form of adenosine triphosphate. When compared to other macronutrient classes, fatty acids yield the most ATP on an energy per gram basis, when they are oxidized to CO2 and water by β-oxidation. Fatty acids are therefore the foremost storage form of fuel in most animals, in addition, fatty acids are important components of the phospholipids that form the phospholipid bilayers out of which all the membranes of the cell are constructed. The prostaglandins made from arachidonic acid stored in the membrane, are probably the most well known group of these local hormones. These lipases are activated by epinephrine and glucagon levels in the blood, caused by declining blood glucose levels after meals. Once freed from glycerol, the fatty acids enter the blood. Long chain free fatty acids enter the cells through specific transport proteins. Acyl-carnitine is shuttled inside by a carnitine-acylcarnitine translocase, as a carnitine is shuttled outside, acyl-carnitine is converted back to acyl-CoA by carnitine palmitoyltransferase II, located on the interior face of the inner mitochondrial membrane. The liberated carnitine is shuttled back to the cytosol, as an acyl-CoA is shuttled into the matrix, each β-oxidative cut of the acyl-CoA molecule yields 5 ATP molecules. The acetyl-CoA produced by β-oxidation enters the citric acid cycle in the mitochondrion by combining with oxaloacetate to form citrate and this results in the complete combustion of the acetyl-CoA to CO2 and water. The energy released in this process is captured in the form of 1 GTP and 11 ATP molecules per acetyl-CoA molecule oxidized and this is the fate of acetyl-CoA wherever β-oxidation of fatty acids occurs, except under certain circumstances in the liver. Under these circumstances acetyl-CoA is diverted to the formation of acetoacetate and beta-hydroxybutyrate, acetoacetate, beta-hydroxybutyrate, and their spontaneous breakdown product, acetone, are frequently, but confusingly, known as ketone bodies. The ketone bodies are released by the liver into the blood, the glycerol released by lipase action is phosphorylated by glycerol kinase in the liver, and the resulting glycerol 3-phosphate is oxidized to dihydroxyacetone phosphate. The glycolytic enzyme triose phosphate isomerase converts this compound to glyceraldehyde 3-phosphate, fatty acids, stored as triglycerides in an organism, are an important source of energy because they are both reduced and anhydrous. The energy yield from a gram of fatty acids is approximately 9 kcal, since the hydrocarbon portion of fatty acids is hydrophobic, these molecules can be stored in a relatively anhydrous environment. Carbohydrates, on the hand, are more highly hydrated. For example,1 g of glycogen can bind approximately 2 g of water and this means that fatty acids can hold more than six times the amount of energy per unit of storage mass
41.
Triacylglycerol
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A triglyceride is an ester derived from glycerol and three fatty acids. Triglycerides are the constituents of body fat in humans and other animals. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, there are many different types of triglyceride, with the main division between saturated and unsaturated types. Saturated fats are saturated with hydrogen – all available places where hydrogen atoms could be bonded to carbon atoms are occupied and these have a higher melting point and are more likely to be solid at room temperature. Unsaturated fats have double bonds between some of the atoms, reducing the number of places where hydrogen atoms can bond to carbon atoms. These have a melting point and are more likely to be liquid at room temperature. Triglycerides are chemically tri esters of fatty acids and glycerol. Triglycerides are formed by combining glycerol with three fatty acid molecules, organic acids have a carboxyl group. Alcohols and organic acids join to form esters, the glycerol molecule has three hydroxyl groups. Each fatty acid has a carboxyl group, the chain lengths of the fatty acids in naturally occurring triglycerides vary, but most contain 16,18, or 20 carbon atoms. Bacteria, however, possess the ability to synthesise odd- and branched-chain fatty acids, as a result, ruminant animal fat contains odd-numbered fatty acids, such as 15, due to the action of bacteria in the rumen. Many fatty acids are unsaturated, some are polyunsaturated, most natural fats contain a complex mixture of individual triglycerides. Because of this, they melt over a range of temperatures. Cocoa butter is unusual in that it is composed of only a few triglycerides, derived from palmitic, oleic, and stearic acids in the 1-, 2-, the simplest triglycerides are those where the three fatty acids are identical. Their names indicate the fatty acid, stearin derived from acid, palmitin derived from palmitic acid. These compounds can be obtained as three forms or polymorphs, α, β, and β′ and these forms differ in terms of their melting points. If the first and third chain R and R″ are different, then the carbon atom is a chiral centre. The pancreatic lipase acts at the bond, hydrolysing the bond. In triglyceride form, lipids cannot be absorbed by the duodenum, fatty acids, monoglycerides, and some diglycerides are absorbed by the duodenum, once the triglycerides have been broken down
. PMID 20376053.
