METHOD FOR INCREASING THE YIELD OF PROPERLY FOLDED RECOMBINANT HUMAN GAMMA-INTERFERON FROM INCLUSION-BODIES

A strategy is described for improved refolding and purification of rec ombinant human gamma interferon (rh-IFN gamma), which could warrant a higher yield and specific activity than reported previously. The optim al conditions of refolding are obtained by addition of a labilizing ag ent, L-arginine, in the refolding buffer. A 10-fold increase in the yi eld was observed with 0.5 M L-arginine, compared with renaturation in its absence. By varying renaturation parameters, the conditions that a llow functional refolding of similar to 25-30% of the recombinant prot ein have been standardized. A simple process is also described for the purification of rh-IFN gamma. The purification involves a single-colu mn chromatography on S-Sepharose, after refolding of rh-IFN gamma in a rginine containing buffer. This procedure has consistently produced rh -IFN gamma having a purity of at least 97%, the rest being the aggrega ted form of gamma interferon. The purified protein is a dimer under no n-denaturing conditions and has a specific activity of 2 x 10(8) IU mg (-1) protein, as measured by viral cytopathic assay. (C) 1996 Elsevier Science B.V. All rights reserved.