Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.5 (neuropathy target esterase)
 1,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent investigations have shown the presence of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine, i.e. the acyl analog of platelet-activating factor (PAF), in unstimulated tissues as well as its formation along with platelet-activating factor upon stimulation of a variety of cells. We demonstrate here that this acyl analog of PAF can be catabolized by purified lysophospholipases I and II from bovine liver with near stoichiometric formation of 2-acetyl-sn-glycero-3-phosphocholine. Lysophospholipase II also deacetylated PAF to lysoPAF and evidence is presented to show that this is an intrinsic activity of this enzyme. This suggested that some lysophospholipases may contribute to intracellular inactivation of PAF by deacetylation. Anion-exchange chromatography of rat liver cytosol confirmed this possibility. However, similar experiments with rat kidney cytosol and rat and human platelet cytosol clearly separated lysophospholipase activities without PAF acetylhydrolase activity from specific PAF acetylhydrolases not having lysophospholipase activity. Thus, lysophospholipases are clearly involved in the metabolism of the acyl analog of PAF and in some tissues, such as liver, may even contribute to abolishing the biological activity of PAF through deacetylation.
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PMID:Catabolism of platelet-activating factor and its acyl analog. Differentiation of the activities of lysophospholipase and platelet-activating-factor acetylhydrolase. 187 23

The group VIA PLA2 is a member of the PLA2 superfamily. This enzyme, which is cytosolic and Ca2+-independent, has been designated iPLA2beta to distinguish it from another recently cloned Ca2+-independent PLA2. Features of iPLA2beta molecular structure offer some insight into possible cellular functions of the enzyme. At least two catalytically active iPLA2beta isoforms and additionalsplicing variants are derived from a single gene that consists of at least 17 exons located on human chromosome 22q13.1. Potential tumor suppressor genes also reside at or near this locus. Structural analyses reveal that iPLA2beta contains unique structural features that include a serine lipase consensus motif (GXSXG), a putative ATP-binding domain, an ankyrin-repeat domain, a caspase-3 cleavage motif DVTD138Y/N, a bipartite nuclear localization signal sequence, and a proline-rich region in the human long isoform. iPLA2beta is widely expressed among mammalian tissues, with highest expression in testis and brain. iPLA2beta prefers to hydrolyze fatty acid at the sn-2 fatty acid substituent but also exhibits phospholipase A1, lysophospholipase, PAF acetylhydrolase, and transacylase activities. iPLA2beta may participate in signaling, apoptosis, membrane phospholipid remodeling, membrane homeostasis, arachidonate release, and exocytotic membrane fusion. Structural features and the existence of multiple splicing variants of iPLA2beta suggest that iPLA2beta may be subject to complex regulatory mechanisms that differ among cell types. Further study of its regulation and interaction with other proteins may yield insight into how its structural features are related to its function.
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PMID:The molecular biology of the group VIA Ca2+-independent phospholipase A2. 1152 80