title: CoA-independent transacylase has characteristics distinct from those of PLA2 enzymes.
abstract: CoA-independent transacylase (CoA-IT) catalyzes the transfer of arachidonic acid from acyl- to alkyl-linked phospholipids. The removal of arachidonic acid from the sn-2 position of the donor phospholipid is a PLA2-like reaction. However, examination of CoA-IT in U937 cells demonstrated that CoA-IT has many characteristics that are distinct from those of PLA2 enzymes, including activity in the absence of Ca2+, activity that was heat and acid unstable and stable in 10 mM 2-mercaptoethanol and that was inhibited by detergents. Compounds that inhibit PLA2 activity did not inhibit CoA-IT activity, including quinacrine, aristolochic acid and arachidonic acid. All of these characteristics of CoA-IT are in contrast to those of most PLA2 enzymes. These data suggest that CoA-IT is biochemically different from, and has a mechanism of action unique from PLA2 enzymes.
authors.affiliation: Department of Pharmacology, SmithKline Beecham Pharmaceutials, King of Prussia, PA 19406.
authors.forename: J D
authors.initials: JD
authors.lastname: Winkler
authors.forename: C M
authors.initials: CM
authors.lastname: Sung
authors.forename: L
authors.initials: L
authors.lastname: Huang
mesh_terms: D000217:Acyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002478:Cells, Cultured; D003902:Detergents / Q000494:pharmacology; D008623:Mercaptoethanol / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D054467:Phospholipases A2
chemical_list: D003902:Detergents; D008623:Mercaptoethanol; D000217:Acyltransferases; C039766:arachidonyl transacylase; D010741:Phospholipases A; D054467:Phospholipases A2