A neutral sphingomyelinase in spermatozoal plasma membranes

Abstract
A highly active neutral sphingomyelinase was observed for the first time in ram spermatozoal plasma membranes. The optimal conditions for the enzyme activity are pH 7.4, 40 mM MgCl2, 40 min of incubation, and 267 nmol sphingomyelin. Ca2+ and cholesterol were found to inhibit sphingomyelinase activity.