The interaction of ram proacrosin and acrosin forms with antiserum raised against ram m beta-acrosin.

An antiserum was raised in rabbits to pure m beta-acrosin, the stable form of active acrosin from ram spermatozoa. By use of immunoprecipitation with Protein A-bearing Staphylococcus aureus cells, so as to react antigen with antibody and isolate the complex rapidly, it could be demonstrated that the anti-m beta-acrosin cross-reacted strongly with native proacrosin, with a degenerate proacrosin form, and with at least one form of active acrosin other than m beta-acrosin. Sperm proteins unrelated to acrosin were not recognized. It is concluded that rabbit anti-m beta-acrosin will react specifically with all the major ram acrosin forms; the antiserum can therefore be used with confidence in immunocytochemical studies to locate both proacrosin and acrosin in ram spermatozoa.