Distribution and removal of the acrosin of bull spermatozoa.

The effects of Hyamine 2389, Triton X-100, Nadeoxycholate, acetic acid and hypertonic KCl and MgCl2 as well as freezing and thawing and sonication were studied on the solubilization of acrosin from washed bull spermatozoa, from Hyamine-pretreated spermatozoa (devoid of cell and outer acrosome membrane and of acrosomal material) and from isolated acrosomal caps and vesicles. Concurrent ultrastructural changes were observed. Hyamine, Triton, KCl, and acetic acid effectively solubilized acrosin from whole spermatozoa but MgCl2 had a poor effect. The outer acrosome membrane and acrosomal material extracted by Hyamine contained about 35-40% of the total acrosin activity, and three quarters of it was soluble. The rest of acrosin situated in the innter acrosome membrane or equatorial segment was best extracted by hypertonic KCl and MgCl2, but the detergents were ineffective in this case indicating that acrosin is bound differently to the outer and inner parts of acrosome. The opposite effect of MgCl2 on the acrosin activities extracted from these two parts could even be a suggestion of multiple forms of acrosin. The increase of the total acrosin activity during the Hyamine treatment indicates that acrosin is partly in an inactive form. due either to steric hindrance, inhibitor complex of existence of a proacrosin.