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

When Hemicentrotus pulcherrimus spermatozoa were treated with egg jelly, phosphatidic acid (PA) content increased with a concomitant decrease 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 indicated 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, which catalyzes the formation of PA, had high substrate specificity for diacyl PC.