Abstract: | Anti-rabbit proacrosin IgG was prepared from goat serum following immunization with a homogeneous preparation of rabbit testis proacrosin. The “auto-activation” products of purified testis proacrosin were separated into 68,000 and 34,000 molecular weight (mol wt) acrosins by Sephadex G-100 column chromatography. Immunodiffusion analysis of testis and epididymal sperm proacrosins and acrosins on agarose gel against goat anti-rabbit testis proacrosin showed immunological identity between rabbit testis and sperm proacrosins and the initial testis acrosin (mol wt 68,000). However, the 34,000 mol wt form of testis acrosin showed weaker reaction with the antibody and only partial identity with the proacrosin and the 68,000 mol wt form of acrosin. These results suggest that there is no major structural difference between testis and sperm proacrosins and between proacrosin and the 68,000 mol wt acrosin, but such a structual change occurs when the 34,000 mol wt acrosin is formed. |