UTILIZATION OF MOLECULAR SPECIES OF DIGLYCERIDES IN SYNTHESIS OF LECITHIN

1. 1. The synthesis of lecithin by rat liver microsomes was measured in the presence of [14C]CDP-choline and three molecular species of diglycerides derived from rat liver lecithin containing four, two and one double bond. The rate of synthesis of lecithin was the same regardless of the fatty acid composition of the diglyceride. 2. 2. Similar results were obtained when different molecular species of diglycerides derived from egg lecithin were used as acceptor molecules. 3. 3. When 3H-labelled monounsaturated and 14C-labelled diunsaturated diglycerides were incubated in different ratios with unlabelled CDP-choline the lecithins produced reflected an identical alteration in isotopic ratio. 4. 4. These results demonstrate that cholinephosphotransferase from rat liver microsomes shows no specificity with respect to the fatty acid composition of the diglycerides, at least for the molecular species investigated so far. © 1969.