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CYP450
Cytochromes P450 (P450s or CYPs) are a superfamily of enzymes containing heme as a cofactor that mostly, but not exclusively, function as monooxygenases. However, they are not omnipresent; for example, they have not been found in ''Escherichia coli''. In mammals, these enzymes oxidize steroids, fatty acids, xenobiotics, and participate in many biosyntheses. By hydroxylation, CYP450 enzymes convert xenobiotics into hydrophilic derivatives, which are more readily excreted. P450s are, in general, the terminal oxidase enzymes in electron transfer chains, broadly categorized as P450-containing systems. The term "P450" is derived from the spectrophotometric peak at the wavelength of the absorption maximum of the enzyme (450 nm) when it is in the reduced state and complexed with carbon monoxide. Most P450s require a protein partner to deliver one or more electrons to reduce the iron (and eventually molecular oxygen). Nomenclature Genes encoding P450 enzymes, and the enzyme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monooxygenase
Monooxygenases are enzymes that incorporate one hydroxyl group (−OH) into substrates in many metabolic pathways. In this reaction, the two atoms of dioxygen are reduced to one hydroxyl group and one H2O molecule by the concomitant oxidation of NAD(P)H. One important subset of the monooxygenases, the cytochrome P450 omega hydroxylases, is used by cells to metabolize arachidonic acid (i.e. eicosatetraenoic acid) to the cell signaling molecules, 20-hydroxyeicosatetraenoic acid or to reduce or totally inactivate the activate signaling molecules for example by hydroxylating leukotriene B4 to 20-hydroxy-leukotriene B5, 5-hydroxyeicosatetraenoic acid to 5,20-dihydroxyeicosatetraenoic acid, 5-oxo-eicosatetraenoic acid to 5-oxo-20-hydroxyeicosatetraenoic acid, 12-hydroxyeicosatetraenoic acid to 12,20-dihydroxyeicosatetraenoic acid, and epoxyeicosatrienoic acids to 20-hydroxy-epoxyeicosatrienoic acids. Classification They are classified as oxidoreductase enzymes that catalyze an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CYP51
In enzymology, a sterol 14-demethylase () is an enzyme of the cytochrome P450 (CYP) superfamily. It is any member of the CYP51 family. It catalysis, catalyzes a chemical reaction such as: :obtusifoliol + 3 O2 + 3 NADPH + 3 H+ \rightleftharpoons 4alpha-methyl-5alpha-ergosta-8,14,24(28)-trien-3beta-ol + formate + 3 NADP+ + 4 H2O The 4 substrate (biochemistry), substrates here are obtusifoliol, oxygen, O2, nicotinamide adenine dinucleotide phosphate, NADPH, and hydrogen ion, H+, whereas its 4 product (chemistry), products are 4alpha-methyl-5alpha-ergosta-8,14,24(28)-trien-3beta-ol, formate, nicotinamide adenine dinucleotide phosphate, NADP+, and water, H2O. Although the lanosterol 14α-demethylase is present in a wide variety of organisms, the enzyme is studied primarily in the context of fungi, where it plays an essential role in mediating membrane permeability. In fungi, CYP51 catalyzes the demethylation of lanosterol to create an important precursor that is eventually converted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Monoxide
Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simplest oxocarbon, carbon oxide. In coordination complexes, the carbon monoxide ligand is called ''metal carbonyl, carbonyl''. It is a key ingredient in many processes in industrial chemistry. The most common source of carbon monoxide is the partial combustion of carbon-containing compounds. Numerous environmental and biological sources generate carbon monoxide. In industry, carbon monoxide is important in the production of many compounds, including drugs, fragrances, and fuels. Indoors CO is one of the most acutely toxic contaminants affecting indoor air quality. CO may be emitted from tobacco smoke and generated from malfunctioning fuel-burning stoves (wood, kerosene, natural gas, propane) and fuel-burning heating systems (wood, oil, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thromboxane-A Synthase
Thromboxane A synthase 1 (, platelet, cytochrome P450, family 5, subfamily A), also known as TBXAS1, is a cytochrome P450 enzyme that, in humans, is encoded by the ''TBXAS1'' gene. Function This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, and other lipids. However, this protein is considered a member of the cytochrome P450 superfamily on the basis of sequence similarity rather than functional similarity. This endoplasmic reticulum membrane protein catalyzes the conversion of prostaglandin H2 to thromboxane A2, a potent vasoconstrictor and inducer of platelet aggregation, and also to 12-Hydroxyheptadecatrienoic acid (i.e. 12-(''S'')-hydroxy-5''Z'',8''E'',10''E''-heptadecatrienoic acid or 12-HHT) an agonist of Leukotriene B4 receptors (i.e. BLT2 receptors) and mediator of certain BLT2 receptor actions. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thromboxane
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for its role in blood clot formation (thrombosis). Production Thromboxane-A synthase, an enzyme found in platelets, converts the arachidonic acid derivative prostaglandin H2 to thromboxane. People with asthma tend to have increased thromboxane production, and analogs of thromboxane act as bronchoconstrictors in patients with asthma. Mechanism Thromboxane acts by binding to any of the thromboxane receptors, G-protein-coupled receptors coupled to the G protein Gq. Functions Thromboxane is a vasoconstrictor and a potent hypertensive agent, and it facilitates platelet aggregation. It is in homeostatic balance in the circulatory system with prostacyclin, a related compound. The mechanism of secretion of thromboxanes from platelets is s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CYP5A1
Thromboxane A synthase 1 (, platelet, cytochrome P450, family 5, subfamily A), also known as TBXAS1, is a cytochrome P450 enzyme that, in humans, is encoded by the ''TBXAS1'' gene. Function This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, and other lipids. However, this protein is considered a member of the cytochrome P450 superfamily on the basis of sequence similarity rather than functional similarity. This endoplasmic reticulum membrane protein catalyzes the conversion of prostaglandin H2 to thromboxane A2, a potent vasoconstrictor and inducer of platelet aggregation, and also to 12-Hydroxyheptadecatrienoic acid (i.e. 12-(''S'')-hydroxy-5''Z'',8''E'',10''E''-heptadecatrienoic acid or 12-HHT) an agonist of Leukotriene B4 receptors (i.e. BLT2 receptors) and mediator of certain BLT2 receptor actions. The e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracetamol
Paracetamol, or acetaminophen, is a non-opioid analgesic and antipyretic agent used to treat fever and mild to moderate pain. It is a widely available over-the-counter drug sold under various brand names, including Tylenol and Panadol. Paracetamol relieves pain in both acute mild migraine and episodic tension headache. At a standard dose, paracetamol slightly reduces fever, though it is inferior to ibuprofen in that respect and the benefits of its use for fever are unclear, particularly in the context of fever of viral origins. The aspirin/paracetamol/caffeine combination also helps with both conditions when the pain is mild and is recommended as a Therapy#Lines of therapy, first-line treatment for them. Paracetamol is effective for post-surgical pain, but is inferior to ibuprofen for this purpose. The paracetamol/ibuprofen combination increases the drugs' potency and is superior to either drug alone. The pain relief paracetamol provides in osteoarthritis is small and clinica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CYP2E1
Cytochrome P450 2E1 (abbreviated CYP2E1, ) is a member of the cytochrome P450 mixed-function oxidase system, which is involved in the metabolism of xenobiotics in the body. This class of enzymes is divided up into a number of subcategories, including CYP1, CYP2, and CYP3, which as a group are largely responsible for the breakdown of foreign compounds in mammals. While CYP2E1 itself carries out a relatively low number of these reactions (~4% of known P450-mediated drug oxidations), it and related enzymes CYP1A2 and CYP3A4 are responsible for the breakdown of many toxic environmental chemicals and carcinogens that enter the body, in addition to basic metabolic reactions such as fatty acid oxidations. CYP2E1 protein localizes to the endoplasmic reticulum and is induced by ethanol, the diabetic state, and starvation. The enzyme metabolizes both endogenous substrates, such as ethanol, acetone, and acetal, as well as exogenous substrates including benzene, carbon tetrachloride, ethyle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italic Type
In typography, italic type is a cursive font based on a stylised form of calligraphic handwriting. Along with blackletter and roman type, it served as one of the major typefaces in the history of Western typography. Owing to the influence from calligraphy, italics normally slant slightly to the right, ''like so''. Different glyph shapes from roman type are usually usedanother influence from calligraphyand upper-case letters may have Swash (typography), swashes, flourishes inspired by ornate calligraphy. Historically, italics were a distinct style of type used entirely separately from roman type, but they have come to be used in conjunction—most fonts now come with a roman type and an oblique type, oblique version (generally called "italic" though often not true italics). In this usage, italics are a way to emphasise key points in a printed text, to identify many types of creative works, to cite foreign words or phrases, or, when quoting a speaker, a way to show which w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Family
A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. One such family are the genes for human hemoglobin subunits; the ten genes are in two clusters on different chromosomes, called the α-globin and β-globin loci. These two gene clusters are thought to have arisen as a result of a precursor gene being duplicated approximately 500 million years ago. Genes are categorized into families based on shared nucleotide or protein sequences. Phylogenetic techniques can be used as a more rigorous test. The positions of exons within the coding sequence can be used to infer common ancestry. Knowing the sequence of the protein encoded by a gene can allow researchers to apply methods that find similarities among protein sequences that provide more information than similarities or differences among DNA sequences. If the genes of a gene family encode proteins, the term ''protein family'' is often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Superfamily
A protein superfamily is the largest grouping (clade) of proteins for which common ancestry can be inferred (see homology (biology), homology). Usually this common ancestry is inferred from structural alignment and mechanistic similarity, even if no sequence similarity is evident. Sequence homology can then be deduced even if not apparent (due to low sequence similarity). Superfamilies typically contain several protein families which show sequence similarity within each family. The term ''protein clan'' is commonly used for protease and glycosyl hydrolases superfamilies based on the MEROPS and CAZy classification systems. Identification Superfamilies of proteins are identified using a number of methods. Closely related members can be identified by different methods to those needed to group the most evolutionarily divergent members. Sequence similarity Historically, the similarity of different amino acid sequences has been the most common method of inferring Sequence homology, h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Nomenclature
Gene nomenclature is the scientific naming of genes, the units of heredity in living organisms. It is also closely associated with protein nomenclature, as genes and the proteins they code for usually have similar nomenclature. An international committee published recommendations for genetic symbols and nomenclature in 1957. The need to develop formal guidelines for human gene names and symbols was recognized in the 1960s and full guidelines were issued in 1979 (Edinburgh Human Genome Meeting). Several other genus-specific research communities (e.g., ''Drosophila'' fruit flies, '' Mus'' mice) have adopted nomenclature standards as well, and have published them on the relevant model organism websites and in scientific journals, including the '' Trends in Genetics'' Genetic Nomenclature Guide. Scientists familiar with a particular gene family may work together to revise the nomenclature for the entire set of genes when new information becomes available. For many genes and their corres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
