PRODUCTION OF DIACYL PHOSPHATIDIC-ACID BY SEA-URCHIN SPERMATOZOA TREATED WITH EGG JELLY

When Hemicentrotus pulcherrimus spermatozoa were treated with egg jell y, phosphatidic acid (PA) content increased with a concomitant decreas e in phosphatidylcholine (PC). Other phospholipids, however, remained at constant levels. The PA produced was composed of 90% diacyl and 10% alkylacyl derivatives. Analysis by gas-liquid chromatography indicate d that the principal fatty acyl residues of diacyl PA were 16:0 at the 1-position and 20:4 and 20:5 at the 2-position. Phospholipase D, whic h catalyzes the formation of PA, had high substrate specificity for di acyl PC.