Synthesis of molecular species of glycerophospholipids from diglyceride-labeled brain microsomes

Selectivity of CDP-choline:diacylglycerol choline phosphotransferase and CDP-ethanolamine:diacylglycerol ethanolamine phosphotransferase for molecular species of diglyceride has been studied in rat brain microsomes in vitro. Diglyceride-labeled microsomes were prepared by incubation with labeled sn-glycerol-3-phosphate; the microsomes were then incubated with CDP-choline or CDP-ethanolamine for different time intervals. Experimental data extrapolated to zero-time incubation were taken into account for evaluating species specificity. A small selectivity for diglyceride species has been demonstrated for the choline phosphotransferase, but the ethanolamine phosphotransferase was found to convert hexaenoic diglyceride into phospholipid at the highest rate.