Folding of eukaryotic proteins produced in Escherichia coli

Although intracellular expression in E. coli may result in accumulation of the eukaryotic protein in inclusion bodies, the protein may often be recovered by first solubilizing with denaturant followed by refolding. Some general guidelines for developing a refolding procedure are apparent but the specific protocol must be empirically determined for each protein. Convenient and rapid assays for detecting native protein are critical for developing a refolding procedure. Maintaining solubility during refolding is a common feature of recovery processes. Proper folding should be assessed by a number of methods including activity, spectroscopic and stability measurements. For some proteins, properly folded protein may be obtained by secretion from E. coli; however, secretion does not ensure correct folding and protection from proteolytic degradation.