Refolding of protein inclusion bodies directly from E. coli homogenate using expanded bed adsorption chromatography.

To avoid the intrinsic problem of aggregation associated with the traditional solution-phase refolding process, we proposed a solid-phase refolding method integrated with the expanded bed adsorption chromatography. The model protein was a fusion protein of recombinant human growth hormone and a glutathione S-transferase fragment. It was demonstrated that the inclusion body proteins in the cell homogenate could be directly refolded with higher yield. To verify the applicability of this method, we have tested with success three types of the starting materials, i.e., rhGH monomer, inclusion bodies containing the fusion protein, and the E. coli cell homogenate. This direct refolding process could reduce the number of the renaturation steps required and allow the refolding at a higher concentration, approximately 2 mg fusion protein per ml resin.