Acyl coenzyme a:phospholipid acyltransferases in porcine platelets discriminate between omega-3 and omega-6 unsaturated fatty acids.

The properties of porcine platelet acyltransferases which catalyze the incorporation of unsaturated fatty acids into the 2 positions of phospholipids were compared with those of porcine liver microsomes and rat liver microsomes. There were significant differences in the relative rates of incorporation of acyl groups into phospholipids as catalyzed by the membranes from different species and organs. The 1-acylglycerophosphate acyltransferase system showed relatively broad specificity for saturated and unsaturated fatty acids, with 14- to 20-carbon chains, while unsaturated acyl-CoAs with 18- and 20-carbon chains were generally good substrates in the acylations of 1-acylglycerophosphocholine and 1-acylglycerophosphoinositol. omega-3 and omega-6 unsaturated fatty acids were recognized differently by different acyltransferase systems in platelets. When activities for combinations of omega-3 and omega-6 unsaturated acyl-CoAs with the same number of carbons and with similar number of double bonds were compared, omega-6 fatty acids were relatively more preferred substrates than omega-3 fatty acids for the 1-acylglycerophosphoinositol acyltransferase system as compared with 1-acylglycerophosphocholine acyltransferase system.