because all of the three inhibitors of motility are hydrolytic products of phosphatidylcholine , and the catalytic enzyme , phospholipase a2 , is known to be calcium dependent , it is suggested that calcium might inhibit sperm motility by activating phospholipase a2 which in turn releases lysophosphatidylcholine and free fatty acids .
C0020291
hydrolytic
C0031667
phospholipase