Affinity sites for beta-glucuronidase on the surface of human spermatozoa.

BARBIERI A; VEISAGA ML; PAOLICCHI L; FORNES WM; SOSA MA; MAYORGA L; BUSTOS-OBREGON E; BERTINI F

ANDROLOGIA

WILEY-BLACKWELL PUBLISHING, INC

Año: 1996 vol. 38 p. 327 - 333

0303-4569

Glycosidases secreted by the epididymis become bound to the surface of spermatozoa duringtheir transit through the epididymal duct. They are believed to play a role in mammalianfertilization. In the present report, we demonstrate that beta-glucuronidase binds to the surfaceof ejaculated human spermatozoa with high affinity and in a saturable manner. The binding isCa(2+)-independent, inhibited by either mannose-6-phosphate, phosphomannan fragmentsfrom the yeast Hansenula holstii and alpha-mannosidase from the Dictyostelium discoideum,suggesting that phosphomannosyl receptors are involved in the recognition of the enzyme. Thecatalytic site of the enzyme is not involved in the binding. The localization of the betaglucuronidasebinding-sites is restricted to the surface of the sperm head. These resultssuggest that the spermatozoa could be the target for glycosidases present in the seminalplasma.