Biliverdin reductase is an enzyme found in all tissues under normal conditions, but especially in reticulo-macrophages of the liver and spleen. BVR facilitates the conversion of biliverdin to bilirubin via the reduction of a double-bond between the second and third pyrrole ring into a single-bond, there are two isozymes, in humans, each encoded by its own gene, biliverdin reductase A and biliverdin reductase B. BVR acts on biliverdin by reducing its double-bond between the rings into a single-bond. It accomplishes this using NADPH + H+ as a donor, forming bilirubin. BVR catalyzes this reaction through a binding site including Lys18, Lys22, Lys179, Arg183. This binding site attaches to biliverdin, and causes its dissociation from heme oxygenase, BVR is composed of two closely packed domains, between 247-415 amino acids long and containing a Rossmann fold. BVR has determined to be a zinc-binding protein with each enzyme protein having one strong-binding zinc atom. The C-terminal half of BVR contains the domain, which adopts a structure containing a six-stranded beta-sheet that is flanked on one face by several alpha-helices. BVR works with the biliverdin/bilirubin redox cycle and it converts biliverdin to bilirubin, which is converted back into biliverdin through the actions of reactive oxygen species.
This cycle allows for the neutralization of ROS, and the reuse of biliverdin products, biliverdin is replenished in the cycle with its formation from heme units through heme oxygenase localized from the endoplasmic reticulum. Bilirubin, being one of the last products of degradation in the liver, is further processed and excreted in bile after conjugation with glucuronic acid. BVR has recently been recognized as a regulator of glucose metabolism and in cell growth and apoptosis control. BVR acts as a means to regenerate bilirubin in a redox cycle without significantly modifying the concentration of available bilirubin. With these levels maintained, it appears that BVR represents a new strategy for the treatment of multiple sclerosis, the mechanism is due to the amplification of the potent antioxidant actions of bilirubin, as this can ameliorate free radical-mediated diseases. Studies have shown that the BVR redox cycle is essential in providing physiological cytoprotection, genetic knock-outs and reduced BVR levels have demonstrated increased formation of ROS, and results in augmented cell death.
Cells that experienced a 90% reduction in BVR experienced three times normal ROS levels
Enoyl-acyl carrier protein reductase
Enoyl-acyl carrier protein reductase, is a key enzyme of the type II fatty acid synthesis system. ENR is a target for narrow-spectrum antibacterial drug discovery because of its essential role in metabolism. In addition, the bacterial ENR sequence and structural organization are distinctly different from those of mammalian fatty acid biosynthesis enzymes, at lower concentrations and Triclocarban provide a bacteriostatic effect by binding to ENR. Atromentin and leucomelone possess antibacterial activity, inhibiting the enzyme in the bacteria Streptococcus pneumoniae, Enoyl- reductase Enoyl- reductase Cis-2-enoyl-CoA reductase NADH-Enoyl ACP Reductase at the US National Library of Medicine Medical Subject Headings EC188.8.131.52
Protocatechuic acid is a dihydroxybenzoic acid, a type of phenolic acid. It is a metabolite of antioxidant polyphenols found in green tea. It has mixed effects on normal and cancer cells in in vitro, protocatechuic acid is antioxidant and anti-inflammatory. PCA extracted from Hibiscus sabdariffa protected against chemically induced liver toxicity in vivo, in vitro testing documented antioxidant and anti-inflammatory activity of PCA, while liver protection in vivo was measured by chemical markers and histological assessment. Depending on the amount of PCA and the time before application, similarly, PCA was reported to increase proliferation and inhibit apoptosis of neural stem cells. In an in vitro model using HL-60leukemia cells, protocatechuic acid showed an antigenotoxic effect, protocatechuic acid can be isolated from the stem bark of Boswellia dalzielii. In the analogous hardening of the ootheca, the phenolic substance concerned is protocatechuic acid. Açaí oil, obtained from the fruit of the palm, is rich in protocatechuic acid.
Protocatechuic acid exists in the skins of some strains of onion as an antifungal mechanism and it is found in Allium cepa. PCA occurs in roselle, which is used worldwide as a food, protocatechuic acid is found in mushrooms such as Agaricus bisporus or Phellinus linteus. Protocatechuic acid is one of the main catechins metabolites found in humans after consumption of green tea infusions, the enzyme protocatechuate 3, 4-dioxygenase uses 3, 4-dihydroxybenzoate and O2 to produce 3-carboxy-cis, cis-muconate
Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst. In most cases, reactions occur faster with a catalyst because they require less activation energy, since they are not consumed in the catalyzed reaction, catalysts can continue to act repeatedly. Often only tiny amounts are required in principle, in the presence of a catalyst, less free energy is required to reach the transition state, but the total free energy from reactants to products does not change. A catalyst may participate in multiple chemical transformations, the effect of a catalyst may vary due to the presence of other substances known as inhibitors or poisons or promoters. Catalyzed reactions have an activation energy than the corresponding uncatalyzed reaction, resulting in a higher reaction rate at the same temperature. However, the mechanics of catalysis is complex. Usually, the catalyst participates in this slowest step, and rates are limited by amount of catalyst, in heterogeneous catalysis, the diffusion of reagents to the surface and diffusion of products from the surface can be rate determining. A nanomaterial-based catalyst is an example of a heterogeneous catalyst, analogous events associated with substrate binding and product dissociation apply to homogeneous catalysts.
Although catalysts are not consumed by the reaction itself, they may be inhibited, deactivated, in heterogeneous catalysis, typical secondary processes include coking where the catalyst becomes covered by polymeric side products. Additionally, heterogeneous catalysts can dissolve into the solution in a system or sublimate in a solid–gas system. The production of most industrially important chemicals involves catalysis, most biochemically significant processes are catalysed. Research into catalysis is a field in applied science and involves many areas of chemistry, notably organometallic chemistry. Catalysis is relevant to aspects of environmental science, e. g. the catalytic converter in automobiles. Many transition metals and transition metal complexes are used in catalysis as well, Catalysts called enzymes are important in biology. A catalyst works by providing a reaction pathway to the reaction product. The rate of the reaction is increased as this route has a lower activation energy than the reaction route not mediated by the catalyst.
The disproportionation of hydrogen peroxide creates water and oxygen, as shown below,2 H2O2 →2 H2O + O2 This reaction is preferable in the sense that the reaction products are more stable than the starting material, though the uncatalysed reaction is slow. In fact, the decomposition of hydrogen peroxide is so slow that hydrogen peroxide solutions are commercially available and this reaction is strongly affected by catalysts such as manganese dioxide, or the enzyme peroxidase in organisms
This enzyme belongs to the family of oxidoreductases, to be specific those acting on the CH-CH group of donor with oxygen as acceptor. The systematic name of this class is bilirubin, oxygen oxidoreductase. This enzyme is called bilirubin oxidase M-1. This enzyme participates in porphyrin and chlorophyll metabolism, two structures of bilirubin oxidase from the ascomycete Myrothecium verrucaria have been deposited in the Protein Data Bank
Coproporphyrinogen III oxidase
Coproporphyrinogen-III oxidase, mitochondrial is an enzyme that in humans is encoded by the CPOX gene. A genetic defect in the results in a reduced production of heme in animals. The medical condition associated with this defect is called hereditary coproporphyria. CPOX, the enzyme of the haem biosynthetic pathway, converts coproporphyrinogen III to protoporphyrinogen IX through two sequential steps of oxidative decarboxylation. The activity of the CPOX enzyme, located in the membrane, is measured in lymphocytes. The protein is a homodimer containing two internally bound iron atoms per molecule of native protein, the enzyme is active in the presence of molecular oxygen that acts as an electron acceptor. The enzyme is widely distributed having been found in a variety of eukaryotic and prokaryotic sources, human CPOX is a mitochondrial enzyme encoded by a 14 kb CPOX gene containing seven exons located on chromosome 3 at q11.2. CPOX is expressed as a 40 kDa precursor and contains an amino terminal mitochondrial targeting signal, after proteolytic processing, the protein is present as a mature form of a homodimer with a molecular mass of 37 kDa.
Hereditary coproporphyria and harderoporphyria are two separate disorders that concern partial deficiency of CPOX. Additionally, it may be associated with abdominal pain and/or skin photosensitivity, hyper-excretion of coproporphyrin III in urine and faeces has been recorded in biochemical tests. HCP is a dominant inherited disorder, whereas harderoporphyria is a rare erythropoietic variant form of HCP and is inherited in an autosomal recessive fashion. Clinically, it is characterized by neonatal haemolytic anaemia, the presence of skin lesions with marked faecal excretion of harderoporphyrin is described in harderoporphyric patients. To date, over 50 CPOX mutations causing HCP have been described, most of these mutations result in substitution of amino acid residues within the structural framework of CPOX. CPOX has been shown to interact with the atypical keto-isocoproporphyrin in human subjects with mercury exposure, coproporphyrinogen III Oxidases at the US National Library of Medicine Medical Subject Headings This article incorporates text from the public domain Pfam and InterPro IPR001260
National Center for Biotechnology Information
The National Center for Biotechnology Information is part of the United States National Library of Medicine, a branch of the National Institutes of Health. The NCBI is located in Bethesda and was founded in 1988 through legislation sponsored by Senator Claude Pepper, the NCBI houses a series of databases relevant to biotechnology and biomedicine and is an important resource for bioinformatics tools and services. Major databases include GenBank for DNA sequences and PubMed, a database for the biomedical literature. Other databases include the NCBI Epigenomics database, all these databases are available online through the Entrez search engine. NCBI is directed by David Lipman, one of the authors of the BLAST sequence alignment program. He leads a research program, including groups led by Stephen Altschul, David Landsman, Eugene Koonin, John Wilbur, Teresa Przytycka. NCBI is listed in the Registry of Research Data Repositories re3data. org, NCBI has had responsibility for making available the GenBank DNA sequence database since 1992.
GenBank coordinates with individual laboratories and other databases such as those of the European Molecular Biology Laboratory. Since 1992, NCBI has grown to other databases in addition to GenBank. The NCBI assigns a unique identifier to each species of organism, the NCBI has software tools that are available by WWW browsing or by FTP. For example, BLAST is a sequence similarity searching program, BLAST can do sequence comparisons against the GenBank DNA database in less than 15 seconds. RAG2/IL2RG The NCBI Bookshelf is a collection of freely accessible, some of the books are online versions of previously published books, while others, such as Coffee Break, are written and edited by NCBI staff. BLAST is a used for calculating sequence similarity between biological sequences such as nucleotide sequences of DNA and amino acid sequences of proteins. BLAST is a tool for finding sequences similar to the query sequence within the same organism or in different organisms. It searches the query sequence on NCBI databases and servers and post the results back to the browser in chosen format.
Input sequences to the BLAST are mostly in FASTA or Genbank format while output could be delivered in variety of such as HTML, XML formatting. HTML is the output format for NCBIs web-page. Entrez is both indexing and retrieval system having data from sources for biomedical research
Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the group on the periodic table and is a highly reactive nonmetal. By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20. 8% of the Earths atmosphere, additionally, as oxides the element makes up almost half of the Earths crust. Most of the mass of living organisms is oxygen as a component of water, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog.
At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone. In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus.
From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract De respiratione. Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, which was the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, one part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. The fact that a substance like wood gains overall weight in burning was hidden by the buoyancy of the combustion products
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Nuclear chemistry is a sub-discipline of chemistry that involves the reactions of unstable. The substance initially involved in a reaction are called reactants or reagents. Chemical reactions are characterized by a chemical change, and they yield one or more products. Reactions often consist of a sequence of individual sub-steps, the elementary reactions. Chemical reactions are described with chemical equations, which present the starting materials, end products. Chemical reactions happen at a characteristic reaction rate at a given temperature, reaction rates increase with increasing temperature because there is more thermal energy available to reach the activation energy necessary for breaking bonds between atoms. Reactions may proceed in the forward or reverse direction until they go to completion or reach equilibrium, Reactions that proceed in the forward direction to approach equilibrium are often described as spontaneous, requiring no input of free energy to go forward.
Non-spontaneous reactions require input of energy to go forward. Different chemical reactions are used in combinations during chemical synthesis in order to obtain a desired product, in biochemistry, a consecutive series of chemical reactions form metabolic pathways. These reactions are catalyzed by protein enzymes. Chemical reactions such as combustion in fire and the reduction of ores to metals were known since antiquity, in the Middle Ages, chemical transformations were studied by Alchemists. They attempted, in particular, to lead into gold, for which purpose they used reactions of lead. The process involved heating of sulfate and nitrate minerals such as sulfate, alum. In the 17th century, Johann Rudolph Glauber produced hydrochloric acid and sodium sulfate by reacting sulfuric acid, further optimization of sulfuric acid technology resulted in the contact process in the 1880s, and the Haber process was developed in 1909–1910 for ammonia synthesis. From the 16th century, researchers including Jan Baptist van Helmont, Robert Boyle, the phlogiston theory was proposed in 1667 by Johann Joachim Becher.
It postulated the existence of an element called phlogiston, which was contained within combustible bodies. This proved to be false in 1785 by Antoine Lavoisier who found the explanation of the combustion as reaction with oxygen from the air