Adenosine Metabolizing Enzymes in Bull and Man Spermatozoa

Abstract

A comparative study on the enzymes involved in the metabolism of adenosine in seminal plasma of bull and man (1) has pointed out that hydrolysis of seminal AMP is carried out by enzymes characterized by significant differences in their kinetic parameters. In both mammals, the kinetic parameters of 5′-nucleotidase, the enzyme which specifically cleaves 5′AMP, are similar. In contrast it is stricking that the level of the enzyme in bull seminal plasma is much higher than in man, where non-specific phosphatases predominate. A different involvement of the enzymic activities in regulating seminal adenosine concentration has been consequently proposed.