Many purified proteins suffer from aggregation during storage and agitation.
This document concerns methods to overcome this process in vitro and to estimate its occurrence in vivo. The recovery of the expressed recombinant protein is usually attempted by solubilising the aggregate with a chemical denaturant and then refolding the protein of interest by dilution of the denaturant. Often only low yields of the recombinant protein are obtained by this route due to aggregation and miss-folding of the unfolded species. Some recent strategies aimed at overcoming the aggregation problem involve addition of a molecular chaperone to the refolding medium. Some success with this approach has been achieved using the GroEL chaperonin from E.coli and fragments of this large protein that can be effectively attached to a chromatographic resin.