Cystathionine beta synthase
Cystathionine-β-synthase, known as CBS, is an enzyme that in humans is encoded by the CBS gene. This enzyme belongs to the family of lyases, to be specific, the hydro-lyases, CBS is a multidomain enzyme composed of an N-terminal enzymatic domain and two CBS domains. The CBS gene is the most common locus for mutations associated with homocystinuria, the systematic name of this enzyme class is L-serine hydro-lyase. Other names in use include, beta-thionase, cysteine synthase, L-serine hydro-lyase, methylcysteine synthase, serine sulfhydrase. Methylcysteine synthase was assigned the EC number EC188.8.131.52 in 1961, a side-reaction of CBS caused this. The EC number EC184.108.40.206 was deleted in 1972, the human enzyme cystathionine β-synthase is a tetramer and comprises 551 amino acids with a subunit molecular weight of 61 kDa. It displays a modular organization of three modules with the N-terminal heme domain followed by a core contains the PLP cofactor. The cofactor is deep in the domain and is linked by a Schiff base.
A Schiff base is a group containing a C=N bond with the nitrogen atom connected to an aryl or alkyl group. The heme domain is composed of 70 amino acids and it appears that the heme only exists in mammalian CBS and is absent in yeast and protozoan CBS. At the C-terminus, the domain of CBS contains a tandem repeat of two CBS domains of β-α-β-β-α, a secondary structure motif found in other proteins. CBS has a C-terminal inhibitory domain, the C-terminal domain of cystathionine β-synthase regulates its activity via both intrasteric and allosteric effects and is important for maintaining the tetrameric state of the protein. This inhibition is alleviated by binding of the effector, adoMet, or by deletion of the regulatory domain, however. Mutations in this domain are correlated with hereditary diseases, the heme domain contains an N-terminal loop that binds heme and provides the axial ligands C52 and H65. The presence of protoporphyrin IX in CBS is a unique PLP-dependent enzyme and is found in the mammalian CBS. D. melanogaster and D.
discoides have truncated N-terminal extensions, the Anopheles gambiae sequence has a longer N-terminal extension than the human enzyme and contains the conserved histidine and cysteine heme ligand residues like the human heme. The PLP is an internal aldimine and forms a Schiff base with K119 in the active site, between the catalytic and regulatory domains exists a hypersensitive site that causes proteolytic cleavage and produces a truncated dimeric enzyme that is more active than the original enzyme. Both truncated enzyme and the found in yeast are not regulated by adoMet
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
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear or contain rings, biochemical modifications such as oxidation or rearrangement produce the related monoterpenoids. Biosynthetically, isopentenyl pyrophosphate and dimethylallyl pyrophosphate are combined to form geranyl pyrophosphate, elimination of the pyrophosphate group leads to the formation of acyclic monoterpenes such as ocimene and the myrcenes. Hydrolysis of the groups leads to the prototypical acyclic monoterpenoid geraniol. Additional rearrangements and oxidations provide compounds such as citral, citronellol, many monoterpenes found in marine organisms are halogenated, such as halomon. In addition to attachments, the isoprene units can make connections to form rings. The most common ring size in monoterpenes is a six-membered ring, a classic example is the cyclization of geranyl pyrophosphate to form limonene. The terpinenes and terpinolene are formed similarly, hydroxylation of any of these compounds followed by dehydration can lead to the aromatic p-cymene.
Important terpenoids derived from monocyclic terpenes are menthol, carvacrol, geranyl pyrophosphate can undergo two sequential cyclization reactions to form bicyclic monoterpenes, such as pinene which is the primary constituent of pine resin. Other bicyclic monoterpenes include carene, sabinene and thujene, camphor and eucalyptol are examples of bicyclic monoterpenoids containing ketone and ether functional groups, respectively. Monoterpenes are emitted by forests and form aerosols that can serve as condensation nuclei. Such aerosols can increase the brightness of clouds and cool the climate, several monoterpenes derivatives have antibacterial activity, such as linalool
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
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
Tryptophan synthase or tryptophan synthetase is an enzyme that catalyzes the final two steps in the biosynthesis of tryptophan. It is commonly found in Eubacteria, Protista, however, it is absent from Animalia. It is typically found as an α2β2 tetramer, the α subunits catalyze the reversible formation of indole and glyceraldehyde-3-phosphate from indole-3-glycerol phosphate. The β subunits catalyze the condensation of indole and serine to form tryptophan in a pyridoxal phosphate dependent reaction. Each α active site is connected to a β active site by a 25 angstrom long hydrophobic channel contained within the enzyme and this facilitates the diffusion of indole formed at α active sites directly to β active sites in a process known as substrate channeling. The active sites of tryptophan synthase are allosterically coupled, Tryptophan synthase typically exists as an α-ββ-α complex. The α and β subunits have molecular masses of 27 and 43 kDa respectively, the α subunit has a TIM barrel conformation.
The β subunit has a fold type II conformation and a site adjacent to the active site for monovalent cations. Their assembly into a complex leads to changes in both subunits resulting in reciprocal activation. There are two mechanisms for intersubunit communication. First, the COMM domain of the β-subunit and the α-loop2 of the α-subunit interact, there are interactions between the αGly181 and βSer178 residues. The active sites are regulated allosterically and undergo transitions between open and closed, states, indole-3-glycerol binding site, See image 1. Indole and serine binding site, See image 1, hydrophobic channel, The α and β active sites are separated by a 25 angstrom long hydrophobic channel contained within the enzyme allowing for the diffusion of indole. If the channel did not exist, the indole formed at an α active site would quickly diffuse away and be lost to the cell as it is hydrophobic, as such, the channel is essential for enzyme complex function. α subunit reaction, The α subunit catalyzes the formation of indole, the αGlu49 and αAsp60 are thought to be directly involved in the catalysis as shown.
The rate limiting step is the isomerization of IGP, β subunit reaction, The β subunit catalyzes the β-replacement reaction in which indole and serine condense to form tryptophan in a PLP dependent reaction. The βLys87, βGlu109, and βSer377 are thought to be involved in the catalysis as shown. Again, the mechanism has not been conclusively determined
Enoyl-CoA hydratase is an enzyme that hydrates the double bond between the second and third carbons on acyl-CoA. This enzyme, known as crotonase, is essential to metabolizing fatty acids to produce both acetyl CoA and energy, note the crystal structure at right of enoyl-coa hydratase from a rat. The crystal structure shows a hexamer formation, which leads to the efficiency of this protein and this enzyme has been discovered to be highly efficient, and allows our bodies to metabolize fatty acids into energy very quickly. In fact this enzyme is so efficient that the rate is equivalent to that of diffusion-controlled reactions, enoyl-CoA hydratase catalyzes the second step in the breakdown of fatty acids or the second step of β-oxidation in fatty acid metabolism shown below. Fatty acid metabolism is how our bodies turn fats or lipids into energy, when fats come into our bodies, they are generally in the form of triacyl-glycerols. These must be broken down in order for the fats to pass into our bodies, when that happens, three fatty acids are released.
In fatty acid metabolism, fatty acids are changed into fatty acyl-CoA, to do this, the carboxylate which occupies one end of the fatty acid is changed into a thioester by substituting coenzyme A for the hydroxyl group. Next the fatty acyl-CoA is oxidized and broken down into an acetyl-CoA molecule, the acetyl CoA is sent to the citric acid cycle while the remaining acyl-CoA is broken down further into acetyl-CoAs. The complete breakdown of a fatty acid not only generates acetyl-CoA molecules and this NADH goes on to be converted into ATP which can be used in other reactions. Enoyl-CoA hydratase is used in β-oxidation to add a hydroxyl group, the enzyme functions by providing two glutamate residues as catalytic acid and base. The two amino acids hold a molecule in place, allowing it to attack in a syn addition to an α-β unsaturated acyl-CoA at the β-carbon. The α-carbon grabs another proton, which completes the formation of the beta-hydroxy acyl-CoA and it is known from experimental data that no other sources of protons reside in the active site.
This means that the proton which the α-carbon grabs is from the water that just attacked the β-carbon, what this implies is that the hydroxyl group and the proton from water are both added from the same side of the double bond, a syn addition. This allows the enzyme to make an S stereoisomer from 2-trans-enoyl-CoA and this is made possible by the two glutamate residues which hold the water in position directly adjacent to the α-β unsaturated double bond, as seen in figure 1. This configuration requires that the site for this enzyme is extremely rigid. The data for a mechanism for this reaction is not conclusive as to whether this reaction is concerted or occurs in consecutive steps, if occurring in consecutive steps, the intermediate is identical to that which would be generated from an E1cb elimination reaction. The enzyme is similar to fumarase. It is classified as EC220.127.116.11, enoyl-CoA Hydratase at the US National Library of Medicine Medical Subject Headings
Enzyme promiscuity is the ability of an enzyme to catalyse a fortuitous side reaction in addition to its main reaction. Although enzymes are remarkably specific catalysts, they can often perform side reactions in addition to their main and these promiscuous activities are usually slow relative to the main activity and are under neutral selection. An example of this is the atrazine chlorohydrolase from Pseudomonas sp, ADP which evolved from melamine deaminase, which has very small promiscuous activity towards atrazine, a man-made chemical. Enzymes are evolved to catalyse a reaction on a particular substrate with a high catalytic efficiency. Several theoretical models exist to predict the order of duplication and specialisation events, on the other, enzymes may evolve an increased secondary activity with little loss to the primary activity with little adaptive conflict. A study of three distinct hydrolases has shown the main activity is robust towards change, whereas the activities are more plastic.
Specifically, selecting for an activity that is not the activity, does not initially diminish the main activity. The most recent and most clear cut example of evolution is the rise of bioremediating enzymes in the past 60 years. Due to the low number of amino acid changes, these provide an excellent model to investigate enzyme evolution in nature. This issue can be resolved thanks to ancestral reconstruction and this variability in ancestral specificity has not only been observed between different genes, but within the same gene family. Antithetically, the ancestor before the split had a more pronounced isomaltose-like glucosidase activity. Roy Jensen in 1976 theorised that primordial enzymes had to be highly promiscuous in order for networks to assemble in a patchwork fashion. This primordial catalytic versatility was lost in favour of highly catalytic specialised orthologous enzymes, as a consequence, many central-metabolic enzymes have structural homologues that diverged before the last universal common ancestor.
Promiscuity is however not only a primordial trait, in fact it is very widespread property in modern genomes, a series of experiments have been conducted to assess the distribution of promiscuous enzyme activities in E. coli. In E. coli 21 out of 104 single-gene knockouts tested could be rescued by overexpressing a noncognate E. coli protein, overexpressing the ORF collection allowed E. coli to gain over an order of magnitude in resistance in 86 out 237 toxic environment. Homologues are sometimes known to display promiscuity towards each others main reactions, despite the divergence the homologues have a varying degree of reciprocal promiscuity, the differences in promiscuity are due to mechanisms involved, particularly the intermediate required. Examples of these are enzymes for primary and secondary metabolism in plants, a promiscuous activity is a non-native activity the enzyme did not evolve to do, but arises due to an accommodating conformation of the active site. When the specificity of enzyme was probed, it was found that it was selective against natural amino acids that were not phenylalanine
Nitrile hydratase is one of the rare enzyme types that use cobalt in a non-corrinoid manner. The mechanism by which the cobalt is transported to NHase without causing toxicity is unclear, although a cobalt permease has been identified, which transports cobalt across the cell membrane. The identity of the metal in the site of a nitrile hydratase can be predicted by analysis of the sequence data of the alpha subunit in the region where the metal is bound. The presence of the amino acid sequence VCTLC indicates a Co-centred NHase, a sequence in genome of the choanoflagellate Monosiga brevicollis was suggested to encode for a nitrile hydratase. The M. brevicollis gene consisted of both the alpha and beta subunits fused into a single gene, NHases have been efficiently used for the industrial production of acrylamide from acrylonitrile and for removal of nitriles from wastewater. Photosensitive NHases intrinsically possess nitric oxide bound to the iron centre, NHases are composed of two types of subunits, α and β, which are not related in amino acid sequence.
NHases exist as αβ dimers or α2β2 tetramers and bind one metal atom per αβ unit, the 3-D structures of a number of NHases have been determined. The α subunit consists of a long extended N-terminal arm, containing two α-helices, and a C-terminal domain with an unusual four-layered structure, an assembly pathway for nitrile hydratase was first proposed when gel filtration experiments found that the complex exists in both αβ and α2β2 forms. In vitro experiments using mass spectrometry further revealed that the α and β subunits first assemble to form the αβ dimer, the dimers can subsequently interact to form a tetramer. The metal centre is located in the cavity at the interface between two subunits. All protein ligands to the atom are provided by the α subunit. The protein ligands to the iron are the sidechains of the three cysteine residues and two mainchain amide nitrogens, the metal ion is octahedrally coordinated, with the protein ligands at the five vertices of an octahedron. The sixth position, accessible to the active site cleft, is occupied either by NO or by a solvent-exchangeable ligand, the two Cys residues coordinated to the metal are post-translationally modified to Cys-sulfinic and -sulfenic acids.
Quantum chemical studies predicted that the Cys-SOH residue might play a role as either a base or as a nucleophile, the functional role of the SOH center as nucleophile has obtained experimental support
In chemistry, a pyrophosphate is a phosphorus oxyanion. Compounds such as salts and esters are called pyrophosphates. The group is called diphosphate or dipolyphosphate, although this should not be confused with phosphates, as a food additive, diphosphates are known as E450. A number of hydrogen pyrophosphates exist, such as Na2H2P2O7, pyrophosphates were originally prepared by heating phosphates. They generally exhibit the highest solubilities among the phosphates, pyrophosphate is the first member of an entire series of polyphosphates. The term pyrophosphate is the name of esters formed by the condensation of a phosphorylated biological compound with inorganic phosphate and this bond is referred to as a high-energy phosphate bond. The synthesis of tetraethyl pyrophosphate was first described in 1854 by Philippe de Clermont at a meeting of the French Academy of Sciences, pyrophosphates are very important in biochemistry. The anion P2O74− is abbreviated PPi and is formed by the hydrolysis of ATP into AMP in cells, ATP → AMP + PPi For example, when a nucleotide is incorporated into a growing DNA or RNA strand by a polymerase, pyrophosphate is released.
The pyrophosphate anion has the structure P2O74−, and is an anhydride of phosphate. This hydrolysis to inorganic phosphate effectively renders the cleavage of ATP to AMP and PPi irreversible, PPi occurs in synovial fluid, blood plasma, and urine at levels sufficient to block calcification and may be a natural inhibitor of hydroxyapatite formation in extracellular fluid. Cells may channel intracellular PPi into ECF, ANK is a nonenzymatic plasma-membrane PPi channel that supports extracellular PPi levels. Defective function of the membrane PPi channel ANK is associated with low extracellular PPi, ectonucleotide pyrophosphatase/phosphodiesterase may function to raise extracellular PPi. AMP + ATP →2 ADP2 ADP +2 Pi →2 ATP The plasma concentration of inorganic pyrophosphate has a range of 0. 58-3.78 µM. Various diphosphates are used as emulsifiers, acidity regulators, raising agents, schröder HC, Kurz L, Muller WE, Lorenz B. Pyrophosphates at the US National Library of Medicine Medical Subject Headings
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 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
Abies grandis is a fir native to the Pacific Northwest and Northern California of North America, occurring at altitudes of sea level to 1,800 m. It is a constituent of the Grand Fir/Douglas Fir Ecoregion of the Cascade Range. The tree typically grows to 40–70 m in height, there are two varieties, the taller coast grand fir, found west of the Cascade Mountains, and the shorter interior grand fir, found east of the Cascades. It was first described in 1831 by David Douglas and it is closely related to white fir. The bark has historical medicinal properties, and it is popular in the United States as a Christmas tree and its lumber is a softwood, and it is harvested as a hem fir. It is used in paper-making, as well as construction for framing and flooring, the grand fir was first described by Scotch botanical explorer David Douglas, who in 1831 collected specimens of the tree along the Columbia River in the Pacific Northwest. Abies grandis is an evergreen coniferous tree growing to 40–70 m tall. The leaves are needle-like, flattened, 3–6 cm long and 2 mm wide by 0.5 mm thick, glossy green above.
The leaf arrangement is spiral on the shoot, but with each leaf variably twisted at the base so they all lie in two flat ranks on either side of the shoot. On the lower surface, two green-white bands of stomata are prominent. The base of leaf is twisted a variable amount so that the leaves are nearly coplanar. Different length leaves, but all lined up in a plane, is a useful way to quickly distinguish this species. The cones are 6–12 cm long and 3. 5–4.5 cm broad, with about 100-150 scales, the bracts are short. The winged seeds are released when the cones disintegrate at maturity about 6 months after pollination, there are two varieties, probably better treated at subspecies rank though not yet formally published as such, Abies grandis var. grandis. Coastal lowland forests, at sea level to 900 m altitude, from Vancouver Island and coastal British Columbia, south to Sonoma County, California, a large, very fast-growing tree to 70 m tall. Foliage strongly flattened on all shoots, cones slightly narrower, with thinner, fairly flexible scales.
Tolerates winter temperatures down to about -25° to -30 °C, growth on good sites may exceed 1.5 m per year when young, a smaller, slow-growing tree to 40–45 m tall. Foliage not strongly flattened on all shoots, the leaves often raised above the shoot, cones slightly stouter, with thicker, slightly woody scales