SYNTHESIS OF PHOSPHATIDYLCHOLINE WITH (N-3) FATTY-ACIDS BY PHOSPHOLIPASE A-2 IN MICROEMULSION

Phosphatidylcholine containing a long chain polyunsaturated acyl group at the 2-position has been prepared by phospholipase A 2 catalyzed esterification of lysophosphatidylcholine with polyunsaturated fatty acids EPA (C20:5) or DHA (C22:6). Preliminary studies showed that the other fatty acids, such as lauric acid (C12), palmitic acid (C16), stearic acid (C18) and linoleic acid (C18:2), were also incorporated. To our knowledge, phospholipase A 2 catalyzed condensation reactions have not been reported in the literature before. The reactions were performed in sodium bis(2-ethylhexyl)-sulfosuccinate-based microemulsions containing small amounts of water. Synthesis of the same phospholipid by transesterification of phosphatidylcholine with the polyunsaturated acids in microemulsion failed; however, enzymatic hydrolysis to lysophosphatidylcholine was facile, quantitative conversion from phosphatidylcholine being attained after 16 hr reaction time. An additional observation was that, unlike enzymatic hydrolysis of phospholipids, the condensation reaction catalyzed by phospholipase A 2 was totally independent of the presence of calcium. © 1990 AOCS Press.