Role of human sperm phospholipase A2 in fertilization: effects of a novel inhibitor of phospholipase A2 activity on membrane perturbations and oocyte penetration.

Phospholipase A 2 was isolated from human sperm and its potential role in the membrane fusion events of fertilization was examined. Highly purified enzyme hydrolyzed the phospholipids of [1- 14 C]oleate-labeled Escherichia coli optimally at neural to alkaline pH with 5 mM CaCl 2 and 150 mM NaCl (specific activity=20 μmol/min/mg). Activity was inhibited in a dose-dependent manner by an oligomer of prostaglandin B 1 (IC 50 =1.5 μM) reported to inhibit human phospholipases A 2 in vitro and in situ