Cyclic AMP-dependent protein kinases in semen from men with subnormal sperm motility or morphology

Photoaffinity labelling by 8-N3-/32P/cAMP of human sperm homogenates with normal pathology and normal progressive motility of the gametes (N) revealed the presence of 2 specific cAMP-binding activities with MW 47 000 (R-I) and 52 000 (R-II). Similar amounts of R-I and R-II were found in sperm homogenates obtained from semen samples with either reduced progressive motility (A50: 30-50% progressive motility and A30: less than 30% progressive motility) or abnormal morphology of the gametes (T: 5-30% normal heads). In contrast, the seminal plasma of the respective semen samples of N, A50, A30 and T incorporated the 8-azido cAMP photolabel in similar quantities into 2 additional cAMP-binding proteins with MW 42 000 and 37 000. Quantitative analysis of the photoaffinity labelling of the seminal plasma obtained from normal (N) or subnormal semen (A50, A30, T) showed that cAMP was predominantly bound to the 37 000 protein. Furthermore, the cAMP-dependent protein kinase and cAMP-binding activities of sperm homogenates were quantitatively comparable within the 4 groups. These results provide the first evidence that neither quantitative nor qualitative differences in the molecular and/or enzymatic properties of cAMP-dependent protein kinases can be detected between normal human sperm (N) and those with either reduced progressive motility (A50, A30) or abnormal morphology (T).