Considerations of sample application and elution during size-exclusion chromatography-based protein refolding

A mechanism for size-exclusion chromatography-based protein refolding is described. The model considers the steps of loading the denatured protein onto a gel filtration column, and protein elution. The model predictions are compared with results of refolding lysozyme (10 and 20 mg/ml) using Superdex 75 HR. The main collapse in protein structure occurred immediately after loading, where the partition coefficient of unfolded lysozyme increased from 0.1 to 0.48 for the partially folded molecule. Use of a refolding buffer as the mobile phase resulted in complete refolding of lysozyme; this eluted at an elution volume of 15.6 ml with a final partition coefficient of 0.54. The model predicted the elution volume of refolded lysozyme at 19.3 ml.