Procedure for refolding IGF-I to an active conformation.

It is provided a method for refolding IGF-I MAL refolding INSOLUBLE, where the IGF-I, HASTY prokaryotic host cells, ES CONCURRENT solubilized unfolded and refolded into a conformation biologically active CUSHION IN A SIMPLE. CUSHION CONTAINING REDUCING AGENT AND chaotropic agent to solubilize the IGF-I CONCENTRATIONS LOW ENOUGH TO ALLOW IT HAPPEN solubilization and refolding. ALSO IS PROVIDED FOR A TRIPLE PROTEASE DEFICIENT E. coli host SUITABLE FOR USE IN THE PROCESS.