['The mode of anchorage of N-acetyl beta-D-glucosaminidase (NAGA) on human ejaculated sperm was investigated.', 'Sperm plasma membrane was prepared by discontinuous sucrose gradient centrifugation from human sperm. NAGA was solubilized from these membranes by two detergents: octyl-glycoside and triton X-100. In separate studies, the release of the enzyme from the sperm membrane preparation by phosphatidylinositol specific phospholipase C (PI-PLC) was also examined.', 'NAGA activity was detected on sperm membranes isolated from human ejaculates. The pattern of the enzyme solubilization by detergents indicated that the enzyme was an integral protein of sperm membrane. NAGA was not released from the sperm membranes by PI-PLC treatment.'] Is n-acetyl beta-D-glucosaminidase attached to human sperm membranes through the glycosylphosphatidyl inositol ( GPI ) -anchor?