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PAF Acetylhydrolase
The enzyme 1-alkyl-2-acetylglycerophosphocholine esterase (EC 3.1.1.47) catalyzes the reaction :1-alkyl-2-acetyl-''sn''-glycero-3-phosphocholine + H2O \rightleftharpoons 1-alkyl-''sn''-glycero-3-phosphocholine + acetate The former is also known as platelet-activating factor. There are multiple enzymes with this function: * Lipoprotein-associated phospholipase A2 * Platelet-activating factor acetylhydrolase 2, cytoplasmic * Platelet-activating factor acetylhydrolase 1b: regulatory subunit 1, catalytic subunit 2, catalytic subunit 3 This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is 1-alkyl-2-acetyl-''sn''-glycero-3-phosphocholine acetohydrolase. Other names in common use include 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine acetylhydrolase, and alkylacetyl-GPC:acetylhydrolase. This enzyme participates in ether lipid metabolism. Structural studies As of late 2007, 7 structures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipoprotein-associated Phospholipase A2
Lipoprotein-associated phospholipase A2 (Lp-PLA2) also known as platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase A2 enzyme that in humans is encoded by the ''PLA2G7'' gene. Lp-PLA2 is a 45-kDa protein of 441 amino acids. It is one of several PAF acetylhydrolases. Function In the blood Lp-PLA2 travels mainly with low-density lipoprotein (LDL). Less than 20% is associated with high-density lipoprotein HDL. Several lines of evidence suggest that HDL-associated Lp-PLA2 may substantially contribute to the HDL antiatherogenic activities. It is an enzyme produced by inflammatory cells and hydrolyzes oxidized phospholipids in LDL. Lp-PLA2 is platelet-activating factor ( PAF) acetylhydrolase (EC 3.1.1.47), a secreted enzyme that catalyzes the degradation of PAF to inactive products by hydrolysis of the acetyl group at the sn-2 position, producing the biologically inactive products LYSO-PAF and acetate. Clinical significance Lp-PLA2 is involved in the developm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAFAH2
Platelet-activating factor acetylhydrolase 2, cytoplasmic is an enzyme that in humans is encoded by the ''PAFAH2'' gene. It is one of several PAF acetylhydrolase The enzyme 1-alkyl-2-acetylglycerophosphocholine esterase (EC 3.1.1.47) catalyzes the reaction :1-alkyl-2-acetyl-''sn''-glycero-3-phosphocholine + H2O \rightleftharpoons 1-alkyl-''sn''-glycero-3-phosphocholine + acetate The former is also know ...s. Function This gene encodes platelet-activating factor acetylhydrolase isoform 2, a single-subunit intracellular enzyme that catalyzes the removal of the acetyl group at the SN-2 position of platelet-activating factor (identified as 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine). However, this lipase exhibits a broader substrate specificity than simply platelet activating factor. Two other isoforms of intracellular platelet-activating factor acetylhydrolase exist, and both are multi-subunit enzymes. Additionally, there is a single-subunit serum isoform of this enzy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAFAH1B1
Platelet-activating factor acetylhydrolase IB subunit alpha is an enzyme that in humans is encoded by the ''PAFAH1B1'' gene. The protein is often referred to as Lis1 and plays an important role in regulating the motor protein Dynein. Function PAFAH1B1 was identified as encoding a gene that when mutated or lost caused the lissencephaly associated with Miller–Dieker syndrome. PAFAH1B1 encodes the non-catalytic alpha subunit of the intracellular Ib isoform of platelet-activating factor acetylhydrolase, a heterotrimeric enzyme that specifically catalyzes the removal of the acetyl group at the SN-2 position of platelet-activating factor (identified as 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine). Two other isoforms of intracellular platelet-activating factor acetylhydrolase exist: one composed of multiple subunits, the other, a single subunit. In addition, a single-subunit isoform of this enzyme is found in serum. According to one study, PAFAH1B1 interacts with VLDLR rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAFAH1B2
Platelet-activating factor acetylhydrolase IB subunit beta is an enzyme that in humans is encoded by the ''PAFAH1B2'' gene. Interactions PAFAH1B2 has been shown to interact with PAFAH1B1. See also * PAFAH1B1 Platelet-activating factor acetylhydrolase IB subunit alpha is an enzyme that in humans is encoded by the ''PAFAH1B1'' gene. The protein is often referred to as Lis1 and plays an important role in regulating the motor protein Dynein. Function ... * PAFAH1B3 References Further reading * * * * * * * * {{gene-11-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAFAH1B3
Platelet-activating factor acetylhydrolase IB subunit gamma is an enzyme that in humans is encoded by the ''PAFAH1B3'' gene. Interactions PAFAH1B3 has been shown to interact with PAFAH1B1 and LNX1. See also * PAFAH1B1 * PAFAH1B2 Platelet-activating factor acetylhydrolase IB subunit beta is an enzyme that in humans is encoded by the ''PAFAH1B2'' gene. Interactions PAFAH1B2 has been shown to interact with PAFAH1B1. See also * PAFAH1B1 Platelet-activating factor acet ... References Further reading * * * * * * * {{gene-19-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolase
Hydrolase is a class of enzyme that commonly perform as biochemical catalysts that use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules. Some common examples of hydrolase enzymes are esterases including lipases, phosphatases, glycosidases, peptidases, and nucleosidases. Esterases cleave ester bonds in lipids and phosphatases cleave phosphate groups off molecules. An example of crucial esterase is acetylcholine esterase, which assists in transforming the neuron impulse into the acetate group after the hydrolase breaks the acetylcholine into choline and acetic acid. Acetic acid is an important metabolite in the body and a critical intermediate for other reactions such as glycolysis. Lipases hydrolyze glycerides. Glycosidases cleave sugar molecules off carbohydrates and peptidases hydrolyze peptide bonds. Nucleosidases hydrolyze the bonds of nucleotides. Hydrolase enzymes are important for the body because they have degra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties. '' Nomenclature Etymology Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Enzymes
This article lists enzymes by their classification in the International Union of Biochemistry and Molecular Biology's Enzyme Commission (EC) numbering system. * List of EC numbers (EC 5) * List of EC numbers (EC 6) :Oxidoreductases (EC 1) (Oxidoreductase) *Dehydrogenase * Luciferase *DMSO reductase :EC 1.1 (act on the CH-OH group of donors) * :EC 1.1.1 (with NAD+ or NADP+ as acceptor) ** Alcohol dehydrogenase (NAD) ** Alcohol dehydrogenase (NADP) **Homoserine dehydrogenase ** Aminopropanol oxidoreductase **Diacetyl reductase **Glycerol dehydrogenase **Propanediol-phosphate dehydrogenase ** glycerol-3-phosphate dehydrogenase (NAD+) ** D-xylulose reductase **L-xylulose reductase **Lactate dehydrogenase **Malate dehydrogenase **Isocitrate dehydrogenase ** HMG-CoA reductase * :EC 1.1.2 (with a cytochrome as acceptor) * :EC 1.1.3 (with oxygen as acceptor) **Glucose oxidase **L-gulonolactone oxidase **Thiamine oxidase **Xanthine oxidase * :EC 1.1.4 (with a disul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ether Lipid Metabolism
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin. Structure and bonding Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. The bonding of oxygen in ethers, alcohols, and water is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tertiary Structure
Protein tertiary structure is the three dimensional shape of a protein. The tertiary structure will have a single polypeptide chain "backbone" with one or more protein secondary structures, the protein domains. Amino acid side chains may interact and bond in a number of ways. The interactions and bonds of side chains within a particular protein determine its tertiary structure. The protein tertiary structure is defined by its atomic coordinates. These coordinates may refer either to a protein domain or to the entire tertiary structure.Branden C. and Tooze J. "Introduction to Protein Structure" Garland Publishing, New York. 1990 and 1991. A number of tertiary structures may fold into a quaternary structure.Kyte, J. "Structure in Protein Chemistry." Garland Publishing, New York. 1995. History The science of the tertiary structure of proteins has progressed from one of hypothesis to one of detailed definition. Although Emil Fischer had suggested proteins were made of polypept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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