Increase in Sperm Type Hexokinase Activity of Rat Spermatozoa During Maturation

Abstract

Rat hexokinases fro caput sperm (immature) and caudal sperm (mature) were investigated. The hexokinases from both sources were studied by DEAE-cellulose column chromatography and by cellulose acetate electrophoresis. The specific activity of caput sperm hexokinase was not significantly different from that of the caudal sperm enzyme. Spermatozoa possess two isozymes of hexokinase. Type I hexokinase was the predominant type in caput sperm whereas the sperm type of hexokinase was predominant in caudal sperm. Hexokinase types II and III were absent in both extracts.

Evidence for a functional glycogen metabolism in mature mammalian spermatozoa

“…However, in recent years, some indications of the presence of a sort of energetic metabolism in the sperm head have been published. Thus, a sperm-specific protein with hexokinase activity related to acrosome reaction and penetration of the oocyte has been described an characterized (Mongkolsirikieat and Boonsaeng, 1980;Kalab et al, 1994), suggesting that some sort of specific hexose phosphorylation is related to the sperm head, where acrosome reaction and the initiation of oocyte penetration start. Moreover, the presence of different types of hexose transporters, such as Glut1, Glut3, and Glut5 in the 10.…”