Expression of native dimers of bovine seminal ribonuclease in a eukaryotic cell system.

Bovine seminal ribonuclease, a uniquely dimeric pancreatic-like RNase, with its dimeric structure stabilized by two intersubunit disulfides, and endowed with special, i.e. non-catalytic, actions (antitumor, immunosuppressive, antispermatogenic), was stably expressed in Chinese hamster ovary cells. The recombinant protein, secreted in the culture medium as a correctly folded dimeric enzyme, was purified to homogeneity and found to be fully active both in its catalytic and antitumor activities.