Activation of temperature-dependent flagellar movement of demembranated fowl spermatozoa: involvement of an endogenous serine protease.

In the presence of ATP, the motility of demembranated fowl spermatozoa was vigorous at 30 degrees C, but negligible at 40 degrees C. Motility could be restored at 40 degrees C by the addition of 10-100 ng trypsin ml-1. Chymotrypsin also stimulated the motility, but neither papain nor carboxypeptidase B appreciably affected motility. Conversely, at 30 degrees C sperm motility was inhibited by aprotinin or phenylmethylsulfonyl fluoride. These results suggest that endogenous protease, presumably serine protease, activity is instrumental in the regulation of fowl sperm motility. It seems likely that the site of action of this protease is axonemal, but a direct effect of added protease on dynein ATPase activity could not be demonstrated.