Formation of diacyl- and alkylacylphosphatidylcholine by the membranes of human platelets.
We have investigated the distribution and fatty acid preference of two acyl-CoA transferase activities in a human platelet mixed membrane fraction and in well-characterised surface and intracellular membrane subfractions prepared from it by high-voltage free-flow electrophoresis. One transferase inserts long-chain unsaturated fatty acids into 1-acyllysophosphatidylcholine (1-acyl-LPC) and the other into lyso-platelet-activating factor (LPAF). Both transferase activities were approx. 4-fold enriched in the intracellular membranes with respect to their specific activities in the mixed membranes. The surface membrane activities were correspondingly depleted. Using 1-acyl-LPC as the acceptor, all the intracellular membrane preparations showed transferase preference for the CoA ester of 8,11,14-eicosatrienoic acid. In contrast when LPAF was the acceptor the CoA esters of linoleic and arachidonic acid were the preferred donors.
D000217:Acyltransferases / Q000097:blood*; D001792:Blood Platelets / Q000201:enzymology / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000097:blood; D010713:Phosphatidylcholines / Q000097:blood*; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000097:blood
D008244:Lysophosphatidylcholines; D010713:Phosphatidylcholines; D010972:Platelet Activating Factor; D000217:Acyltransferases