Synthesis of 6-phosphatidyl-L-ascorbic acid by phospholipase D.

Phospholipase D (EC 3.1.4.4) of Streptomyces species was found to catalyze transphosphatidylation to L-ascorbic acid from phosphatidylcholine (PC) in a biphasic reaction system. The product was identified as 1,2-diacyl-sn-glycero-3-phospho-6'-L-ascorbic acid (PA-AsA) by mass spectrometry and nuclear magnetic resonance spectroscopy. The optimal pH of transphosphatidylation was 4.5 and the rate of PA-AsA formation increased as concentrations of L-ascorbic acid increased. The conversion of PC to PA-AsA was greater than 80%. PA-AsA was found to be more resistant to hydrolysis by phospholipase D than was PC.