Purification and properties of pyridine nucleosidase (glycosidase) from bull semen.

A soluble pyridine nucleotidase was first described in bull semen by Leone and Bonaduce (1). During studies on the specificity of this enzyme, we observed that passage of dilute semen through a column composed of calcium phosphate gel and diethylaminoethyl cellulose anion exchanger (Whatman)] resulted in a preparation of high specific activity. In this single purification step the specific activity of the enzyme achieved was two to three times that of the best reported preparations (1). This material could be further purified to a high degree through relatively simple steps involving various forms of cellulose columns. The purified enzyme catalyzed the hydrolysis and imidazolysis of both diand triphosphopyridine nucleotide. Most interestingly, it also catalyzed the hydrolysis and imidazolysis of nicotinamide mononucleotide. N-(ring)-Ribosylnicotinamide was also attacked. In the present paper we report the procedure for the purification of this enzyme and certain observations on its specificity and physicochemical properties.