Bull Semen Ribonucleases. 1. Purification and Physico-Chemical Properties of the Major Component

A high ribonuclease activity has been detected in bull seminal plasma; two major fractions (RNAase BS-1 and RNAase BS-2) have been identified, which are responsible for such activity and one of the two, RNAase BS-1, has been purified and crystallized. It has a molecular weight of 29000, an isoelectric point at pH 10.3 and A1%1 cm at 278 nm is 4.65. The amino acid composition has been determined, its main features being a high content of basic residues, the absence of tryptophan and eysteine, and the presence of 18 half-cystine residues. The enzyme is produced by the seminal vesicles, and occurs in seminal plasma as a free, soluble component.