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12-HETE
12-Hydroxyeicosatetraenoic acid (12-HETE) is a derivative of the 20 carbon polyunsaturated fatty acid, arachidonic acid, containing a hydroxyl residue at carbon 12 and a 5''Z'',''8Z'',10''E'',14''Z'' cis–trans configuration (Z=cis, E=trans) in its four double bonds. It was first found as a product of arachidonic acid metabolism made by human and bovine platelets through their 12''S''-lipoxygenase (i.e. ALOX12) enzyme(s). However, the term 12-HETE is ambiguous in that it has been used to indicate not only the initially detected "S" stereoisomer, 12''S''-hydroxy-5''Z'',''8Z'',10''E'',14''Z''-eicosatetraenoic acid (12(''S'')-HETE or 12''S''-HETE), made by platelets, but also the later detected "R" stereoisomer, 12(''R'')-hydroxy-5''Z'',''8Z'',10''E'',14''Z''-eicosatetraenoic acid (also termed 12(''R'')-HETE or 12''R''-HETE) made by other tissues through their 12''R''-lipoxygenase enzyme, ALOX12B. The two isomers, either directly or after being further metabolized, have been sugges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arachidonate 12-lipoxygenase
ALOX12 (), also known as arachidonate 12-lipoxygenase, 12-lipoxygenase, 12''S''-Lipoxygenase, 12-LOX, and 12''S''-LOX is a lipoxygenase-type enzyme that in humans is encoded by the ''ALOX12'' gene which is located along with other lipoyxgenases on chromosome 17p13.3. ALOX12 is 75 kilodalton protein composed of 663 amino acids. Nomenclature Other systematic names for ALOX12 include 12S-Lipoxygenase, platelet-type 12-lipoxygenase, arachidonate:oxygen 12-oxidoreductase, Delta12-lipoxygenase, 12Delta-lipoxygenase, and C-12 lipoxygenase. ALOX12, often termed plate platelet-type 12-lipoxygenase, is distinguished from leukocyte-type 12-lipoxygenase which is found in mice, rats, cows, and pigs but not humans. Leukocyte-type 12-lipoxygenase in these animal species shares 73-86% amino acid identity with human ALOX15 but only 57-66% identity with human platelet-type 12-lipoxygenase and, like ALOX15, metabolizes arachidonic acid primarily to 15(''S'')-hydroperoxy-5''Z'',8''Z'',11''Z'',13' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arachidonic Acid
Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega−6 fatty acid 20:4(ω−6), or 20:4(5,8,11,14). It is a precursor in the formation of leukotrienes, prostaglandins, and thromboxanes. Together with omega−3 fatty acids and other omega−6 fatty acids, arachidonic acid provides energy for body functions, contributes to cell membrane structure, and participates in the synthesis of eicosanoids, which have numerous roles in physiology as signaling molecules. Its name derives from the ancient Greek neologism ''arachis'' 'peanut', although peanut oil does not contain any arachidonic acid. Arachidonate is the name of the derived carboxylate anion ( conjugate base of the acid), salts, and some esters. Chemistry In chemical structure, arachidonic acid is a carboxylic acid with a 20-carbon chain and four '' cis''- double bonds; the first double bond is located at the sixth carbon from the omega end. Some chemistry sources define 'arachidonic acid' to designa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipoxygenase
Lipoxygenases () (LOX) are a family of (non- heme) iron-containing enzymes, more specifically oxidative enzymes, most of which catalyze the dioxygenation of polyunsaturated fatty acids in lipids containing a cis,cis-1,4- pentadiene into cell signaling agents that serve diverse roles as autocrine signals that regulate the function of their parent cells, paracrine signals that regulate the function of nearby cells, and endocrine signals that regulate the function of distant cells. The lipoxygenases are related to each other based upon their similar genetic structure and dioxygenation activity. However, one lipoxygenase, ALOXE3, while having a lipoxygenase genetic structure, possesses relatively little dioxygenation activity; rather its primary activity appears to be as an isomerase that catalyzes the conversion of hydroperoxy unsaturated fatty acids to their 1,5- epoxide, hydroxyl derivatives. Lipoxygenases are found in eukaryotes (plants, fungi, animals, protists); whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
15-hydroxyicosatetraenoic Acid
15-Hydroxyeicosatetraenoic acid (also termed 15-HETE, 15(''S'')-HETE, and 15''S''-HETE) is an eicosanoid, i.e. a metabolite of arachidonic acid. Various cell types metabolize arachidonic acid to 15(''S'')-hydroperoxyeicosatetraenoic acid (15(''S'')-HpETE). This initial Peroxide, hydroperoxide product is extremely short-lived in cells: if not otherwise metabolized, it is rapidly reduced to 15(''S'')-HETE. Both of these metabolites, depending on the cell type which forms them, can be further metabolized to 15-oxo-eicosatetraenoic acid (15-oxo-ETE), 5(''S''),15(''S'')-dihydroxy-eicosatetraenoic acid (5(''S''),15(''S'')-diHETE), 5-oxo-15(''S'')-hydroxyeicosatetraenoic acid (5-oxo-15(''S'')-HETE), a subset of specialized pro-resolving mediators viz., the lipoxins, a class of pro-inflammatory mediators, the eoxins, and other products that have less well-defined activities and functions. Thus, 15(''S'')-HETE and 15(''S'')-HpETE, in addition to having intrinsic biological activities, are ke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arachidonate 15-lipoxygenase
ALOX15 (also termed arachidonate 15-lipoxygenase, 15-lipoxygenase-1, 15-LO-1, 15-LOX-1) is, like other lipoxygenases, a seminal enzyme in the metabolism of polyunsaturated fatty acids to a wide range of physiologically and pathologically important products. ▼ Gene Function Kelavkar and Badr (1999) stated that the ALOX15 gene product is implicated in antiinflammation, membrane remodeling, and cancer development/metastasis. Kelavkar and Badr (1999) described experiments yielding data that supported the hypothesis that loss of the TP53 gene, or gain-of-function activities resulting from the expression of its mutant forms, regulates ALOX15 promoter activity in human and in mouse, albeit in directionally opposite manners. These studies defined a direct link between ALOX15 gene activity and an established tumor-suppressor gene located in close chromosomal proximity. Kelavkar and Badr (1999) referred to this as evidence that 15-lipoxygenase is a mutator gene. ▼ Mapping By PCR ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepoxilin
Hepoxilins (Hx) are a set of epoxyalcohol metabolites of polyunsaturated fatty acids (PUFA), i.e. they possess both an epoxide and an alcohol (i.e. hydroxyl) residue. HxA3, HxB3, and their non-enzymatically formed isomers are nonclassic eicosanoid derived from acid the (PUFA), arachidonic acid. A second group of less well studied hepoxilins, HxA4, HxB4, and their non-enzymatically formed isomers are nonclassical eicosanoids derived from the PUFA, eicosapentaenoic acid. Recently, 14,15-HxA3 and 14,15-HxB3 have been defined as arachidonic acid derivatives that are produced by a different metabolic pathway than HxA3, HxB3, HxA4, or HxB4 and differ from the aforementioned hepoxilins in the positions of their hydroxyl and epoxide residues. Finally, hepoxilin-like products of two other PUFAs, docosahexaenoic acid and linoleic acid, have been described. All of these epoxyalcohol metabolites are at least somewhat unstable and are readily enzymatically or non-enzymatically to their correspo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyunsaturated Fatty Acid
In biochemistry and nutrition, a polyunsaturated fat is a fat that contains a polyunsaturated fatty acid (abbreviated PUFA), which is a subclass of fatty acid characterized by a backbone with two or more carbon–carbon double bonds. Some polyunsaturated fatty acids are essentials. Polyunsaturated fatty acids are precursors to and are derived from polyunsaturated fats, which include drying oils. Nomenclature The position of the carbon-carbon double bonds in carboxylic acid chains in fats is designated by Greek letters. The carbon atom closest to the carboxyl group is the ''alpha'' carbon, the next carbon is the ''beta'' carbon and so on. In fatty acids the carbon atom of the methyl group at the end of the hydrocarbon chain is called the ''omega'' carbon because ''omega'' is the last letter of the Greek alphabet. Omega-3 fatty acids have a double bond three carbons away from the methyl carbon, whereas omega-6 fatty acids have a double bond six carbons away from the methyl ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diastereomer
In stereochemistry, diastereomers (sometimes called diastereoisomers) are a type of stereoisomer. Diastereomers are defined as non-mirror image, non-identical stereoisomers. Hence, they occur when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the equivalent (related) stereocenters and are not mirror images of each other. When two diastereoisomers differ from each other at only one stereocenter, they are epimers. Each stereocenter gives rise to two different configurations and thus typically increases the number of stereoisomers by a factor of two. Diastereomers differ from enantiomers in that the latter are pairs of stereoisomers that differ in all stereocenters and are therefore mirror images of one another. Enantiomers of a compound with more than one stereocenter are also diastereomers of the other stereoisomers of that compound that are not their mirror image (that is, excluding the opposing enantiomer). Diastereomers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoxide
In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen. This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile. Nomenclature A compound containing the epoxide functional group can be called an epoxy, epoxide, oxirane, and ethoxyline. Simple epoxides are often referred to as oxides. Thus, the epoxide of ethylene (C2H4) is ethylene oxide (C2H4O). Many compounds have trivial names; for instance, ethylene oxide is called "oxirane". Some names emphasize the presence of the epoxide functional group, as in the compound ''1,2-epoxyheptane'', which can also be called ''1,2-heptene oxide''. A polymer formed from epoxide precursors is called an ''epoxy''. However, few if any of the epoxy groups i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulinoma
An insulinoma is a tumour of the pancreas that is derived from beta cells and secretes insulin. It is a rare form of a neuroendocrine tumour. Most insulinomas are benign in that they grow exclusively at their origin within the pancreas, but a minority metastasize. Insulinomas are one of the functional pancreatic neuroendocrine tumour (PNET) group ("functional" because it increases production of insulin). In the Medical Subject Headings classification, insulinoma is the only subtype of "islet cell adenoma". Beta cells secrete insulin in response to increases in blood glucose. The resulting increase in insulin acts to lower blood glucose back to normal levels, the point at which further secretion of insulin is stopped. In contrast, the secretion of insulin by insulinomas is rather independent of blood glucose; these tumours continue to secrete insulin, causing blood glucose levels to fall further below normal. As a result, patients present symptoms of low blood glucose (hypogly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enantiomer
In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities which are mirror images of each other and non-superposable. Enantiomer molecules are like right and left hands: one cannot be superposed onto the other without first being converted to its mirror image. It is solely a relationship of chirality (chemistry), chirality and the permanent three-dimensional relationships among molecules or other chemical structures: no amount of re-orientation of a molecule as a whole or conformational isomerism, conformational change converts one chemical into its enantiomer. Chemical structures with chirality rotate plane-polarized light. A mixture of equal amounts of each enantiomer, a ''racemic mixture'' or a ''racemate'', does not rotate light. Stereoisomers include both enantiomers and diastereomers. Diaste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
