Inhibitors of Arachidonate Metabolism and Effects on PAF Production

Our understanding of the enzyme Coenzyme A-independent transacylase (CoA-IT) has increased dramatically over the last 10 years. The enzyme catalyses the removal of the fatty acyl group from the sn-2 position of glycerophospholipids (GPL) and transfers it into 1-radyl-2-lyso GPL.1 The enzyme shows striking selectivity for transfer of arachidonate and other long-chain, unsaturated fatty acyl groups. It also shows strong preference for phosphocholine-and phosphoethanolamine-containing GPL, along with a preference for using 1-ether GPL as acceptors for the transferred arachidonate.2 The mechanism of action of CoA-IT has yet to be defined at the molecular level, but CoA-IT is hypothesized to be a member of the family of tranferases typified by lecithin-cholesterol acyl transferase.3 Based on these characteristics, CoA-IT has been presumed to play a role in the movement of arachidonate between GPL that occurs in inflammatory cells.4–7