ISOTYPES OF PROTEIN-KINASE-C IN BOVINE SPERM

Protein kinase C is present in bovine epididymal sperm. The enzyme was partially purified by gel filtration on Sephacryl S-300. The Ca2+/phosphatidylserine-dependent histone phosphotransferase activity elutes from the gel filtration column in a manner corresponding to a Mr ~80 kDa. The activity peak also corresponds with [3H]phorbol 12,13-dibutyrate binding activity. Immunoblot analysis of the partially purified enzyme with isozyme-specific monoclonal antibodies revealed the presence of α-, β-, and γ-subspecies of protein kinase C. Indirect immunofluorescence showed that the antibodies against α-, β-, and γ-subspecies produced prominent staining of the postacrosomal region of the sperm head. In addition, β-subspecies antibodies produced minor staining of the midpiece and γ-subspecies antibodies produced a minor staining of the acrosomal region. © 1992.