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ALOXE3
Epidermis-type lipoxygenase 3 (ALOXE3 or eLOX3) is a member of the lipoxygenase family of enzymes; in humans, it is encoded by the ''ALOXE3'' gene. This gene is located on chromosome 17 at position 13.1 where it forms a cluster with two other lipoxygenases, ALOX12B and ALOX15B. Among the human lipoxygenases, ALOXE3 is most closely (54% identity) related in amino acid sequence to ALOX12B. ALOXE3, ALOX12B, and ALOX15B are often classified as epidermal lipoxygenases, in distinction to the other three human lipoxygenases (ALOX5, ALOX12, and ALOX15), because they were initially defined as being highly or even exclusively expressed and functioning in skin. The epidermis-type lipoxygenases are now regarded as a distinct subclass within the multigene family of mammalian lipoxygenases with mouse Aloxe3 (also termed e-Lox-3) being the ortholog to human ALOXE3, mouse Alox12b being the ortholog to human ALOX12B (MIM 603741), and mouse Alox8 being the ortholog to human ALOX15B (MIM 603697) upp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipoxygenase
Lipoxygenases () are a family of (non-heme) iron-containing 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); while the third domain of terrestrial life, the archaea, pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALOX12B
Arachidonate 12-lipoxygenase, 12R type, also known as ALOX12B, 12''R''-LOX, and arachidonate lipoxygenase 3, is a lipoxygenase-type enzyme composed of 701 amino acids and encoded by the ''ALOX12B'' gene. The gene is located on chromosome 17 at position 13.1 where it forms a cluster with two other lipoxygenases, ALOXE3 and ALOX15B. Among the human lipoxygenases, ALOX12B is most closely (54% identity) related in amino acid sequence to ALOXE3 Activity ALOX12B oxygenates arachidonic acid by adding molecular oxygen (O2) in the form of a hydroperoxyl (HO2) residue to its 12th carbon thereby forming 12(''R'')-hydroperoxy-5''Z'',8''Z'',10''E'',14''Z''-icosatetraenoic acid (also termed 12(''R'')-HpETE or 12''R''-HpETE). When formed in cells, 12''R''-HpETE may be quickly reduced to its hydroxyl analog (OH), 12(''R'')-hydroxy-5Z'',8''Z'',10''E'',14''Z''-eicosatetraenoic acid (also termed 12(''R'')-HETE or 12''R''-HETE), by ubiquitous peroxidase-type enzymes. These sequential metabolic r ... [...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 correspon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALOX12
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] |
Very Long Chain Fatty Acid
A very-long-chain fatty acid (VLCFA) is a fatty acid with 22 or more carbons. Their biosynthesis occurs in the endoplasmic reticulum. VLCFA's can represent up to a few percent of the total fatty acid content of a cell. Unlike most fatty acids, VLCFAs are too long to be metabolized in the mitochondria, in the endoplasmic reticulum (ER) in plants and must be metabolized in peroxisomes. Certain peroxisomal disorders, such as adrenoleukodystrophy and Zellweger syndrome, can be associated with an accumulation of VLCFAs. Enzymes that produce VLCFAs are the targets of herbicides including pyroxasulfone. Major VLCFAs Some of the more common saturated VLCFAs: lignoceric acid (C24), cerotic acid (C26), montanic acid (C28), melissic acid (C30), lacceroic acid (C32), ghedoic acid (C34), and the odd-chain fatty acid ceroplastic acid (C35). Several monounsaturated VLCFAs are also known: nervonic acid (Δ15-24:1), ximenic acid (Δ17-26:1), and lumequeic acid (Δ21-30:1). See also * AC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through transepidermal water loss. The epidermis is composed of multiple layers of flattened cells that overlie a base layer (stratum basale) composed of columnar cells arranged perpendicularly. The layers of cells develop from stem cells in the basal layer. The human epidermis is a familiar example of epithelium, particularly a stratified squamous epithelium. The word epidermis is derived through Latin , itself and . Something related to or part of the epidermis is termed epidermal. Structure Cellular components The epidermis primarily consists of keratinocytes ( proliferating basal and differentiated suprabasal), which comprise 90% of its cells, but also contains melanocytes, Langerhans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Esterified
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 The word '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxyl
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy groups. Both the negatively charged anion , called hydroxide, and the neutral radical , known as the hydroxyl radical, consist of an unbonded hydroxy group. According to IUPAC definitions, the term ''hydroxyl'' refers to the hydroxyl radical () only, while the functional group is called a ''hydroxy group''. Properties Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be readily deprotonated due to a large difference between the electronegativity of oxygen (3.5) and that of hydrogen (2.1). Hydroxy-containing compounds engage in intermolecular hydrogen bonding increasing the electrostatic attraction between molecules and thus to higher boiling and melting points than found for compounds that lack this f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amide
In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it is part of the main chain of a protein, and an isopeptide bond when it occurs in a side chain, such as in the amino acids asparagine and glutamine. It can be viewed as a derivative of a carboxylic acid () with the hydroxyl group () replaced by an amine group (); or, equivalently, an acyl (alkanoyl) group () joined to an amine group. Common examples of amides are acetamide (), benzamide (), and dimethylformamide (). Amides are qualified as primary, secondary, and tertiary according to whether the amine subgroup has the form , , or , where R and R' are groups other than hydrogen. The core of amides is called the amide group (specifically, carboxamide group). Amides are pervasive in nature and technology. Proteins and important plastics l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratum Corneum
The stratum corneum (Latin for 'horny layer') is the outermost layer of the epidermis. The human stratum corneum comprises several levels of flattened corneocytes that are divided into two layers: the ''stratum disjunctum'' and ''stratum compactum''. The skin's protective acid mantle and lipid barrier sit on top of the stratum disjunctum. The stratum disjunctum is the uppermost and loosest layer of skin. The stratum compactum is the comparatively deeper, more compacted and more cohesive part of the stratum corneum. The corneocytes of the stratum disjunctum are larger, more rigid and more hydrophobic than that of the stratum compactum. The stratum corneum is the dead tissue that performs protective and adaptive physiological functions including mechanical shear, impact resistance, water flux and hydration regulation, microbial proliferation and invasion regulation, initiation of inflammation through cytokine activation and dendritic cell activity, and selective permeability to exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingosine
Sphingosine (2-amino-4-trans-octadecene-1,3-diol) is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms a primary part of sphingolipids, a class of cell membrane lipids that include sphingomyelin, an important phospholipid. Functions Sphingosine can be phosphorylated in vivo via two kinases, sphingosine kinase type 1 and sphingosine kinase type 2. This leads to the formation of sphingosine-1-phosphate, a potent signaling lipid. Sphingolipid metabolites, such as ceramides, sphingosine and sphingosine-1-phosphate, are lipid signaling molecules involved in diverse cellular processes. Biosynthesis Sphingosine is synthesized from palmitoyl CoA and serine in a condensation required to yield dihydrosphingosine. Dehydrosphingosine is then reduced by NADPH to dihydrosphingosine (sphinganine), acylated to dihydroceramide finally oxidized by FAD to ceramide. Sphingosine is then solely formed via degradation of sphingolipid in the lysosome. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceramide
Ceramides are a family of waxy lipid molecules. A ceramide is composed of N-acetylsphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of eukaryotic cells, since they are component lipids that make up sphingomyelin, one of the major lipids in the lipid bilayer. Contrary to previous assumptions that ceramides and other sphingolipids found in cell membrane were purely supporting structural elements, ceramide can participate in a variety of cellular signaling: examples include regulating differentiation, proliferation, and programmed cell death (PCD) of cells. The word ''ceramide'' comes from the Latin ''cera'' (wax) and ''amide''. Ceramide is a component of vernix caseosa, the waxy or cheese-like white substance found coating the skin of newborn human infants. Pathways for ceramide synthesis There are three major pathways of ceramide generation. First, the sphingomyelinase pathway uses an enzyme to break down sphingomyelin in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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