Refolding and Purification of Recombinant Human Granulocyte Colony-Stimulating Factor Expressed in Escherichia coli Using Protein Folding Liquid Chromatography

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) in the form of inclusion bodies expressed in Escherichia coli (E. coli) was simultaneously refolded and purified using protein folding liquid chromatography (PFLC). Cu2+-iminodiacetic acid (IDA) Sepharose was selected as the stationary phase for immobilized metal ion affinity chromatography. rhG-CSF was purified and the aggregates were diminished under a linear gradient elution of imidazole in the presence of a suitable concentration of urea. Using only one PFLC run, the refolded rhG-CSF had a specific bioactivity of 1.8 × 108 IU/mg and a purity of 97%, with the mass recovery of 32%.