REFOLDING KINETICS OF HIGH-CONCENTRATION DENATURED PROTEIN BY FED-BATCH OPERATION WITH DILUTION ADDITIVES

Oxidative refolding of denatured-reduced lysozyme at 5 mg·ml~(-1) was performed by fed-batch operation with dilution additives(acetamide and glycerol).A kinetic model based on the three-state protein model was established to describe the refolding process, and the refolding and aggregation constants were obtained by fitting the model to the experimental data.At a lower GdmCl concentration (1 mol·L~(-1)) and a proper acetamide concentration (5 mol·L~(-1)), the refolding of lysozyme could reach a yield higher than 80%.When GdmCl concentration was decreased, acetamide concentration should be properly increased to achieve a high refolding yield.This indicated the same effect of acetamide and GdmCl on protein refolding.In contrast, glycerol facilitated the refolding of lysozyme by enhancing the thermodynamic stability of native-state protein.This meant that glycerol was cooperative with GdmCl on facilitating protein refolding, and its addition could only give a high yield at a proper GdmCl concentration.