High level production of bovine angiogenin in E. coli by an efficient refolding procedure.

Recombinant bovine angiogenin (rbAng) was expressed in E. coli at up to 30% of total cell proteins but was produced as inclusion bodies. By investigating the effect of various factors on the refolding yield, we obtained about 60% refolding. After chromatographic purification, about 60 mg purified angiogenin was obtained from 1 l culture. The purified recombinant bovine angiogenin was identical to native bovine angiogenin (nbAng) obtained from cow's milk. Our approach is highly efficient and can be generally used for the production of various types of angiogenin for functional and structural studies as well as therapeutic purposes.