A method for distinguishing 1-acyl from 2-acyl lysophosphatidylcholines generated in biological systems

Phospholipases A(1) and A(2) frequently coexist in biological systems. Gene ration of lysophosphatidylcholine (LPC) in such systems cannot be assigned to any of these types of enzymes unless the position of the fatty acid in t he lysocompound can be unambiguously determined. We here present a simple m ethod to achieve this purpose. It is based on the initial chemical acylatio n of the isolated LPC with a labeled fatty acid, followed by the enzymatic analysis of the resulting phosphatidylcholine (PC), using snake or bee veno m phospholipase A(2). Thus, if treatment of the PC with this enzyme release s a labeled free fatty acid, it is demonstrated that the initial LPC was ac ylated at position sn-l, whereas if the product of hydrolysis yields labele d LPC, then the initial LPC was acylated at position sn-2. This is the firs t method devised to determine the source of LPC in the presence of mixtures of phospholipases A(1) and A(2) in complex biological systems. (C) 1999 Ac ademic Press.