PROTEIN TAILORING OF HUMAN GRANULOCYTE-COLONY-STIMULATING FACTOR

Recombinant human granulocyte-colony stimulating factor (rhG-CSF) was modified by site-directed mutagenesis and chemical modification in order to improve its pharmacological activity and its thermostability. The mutant rhG-CSF which 17th cysteine was substituted with alanine was chemically modified by activated polyethylene glycol. The chemically modified mutant rhG-CSF greatly increased both its biological activity in vivo and its thermostability. This is a successful example of protein tailoring in which site-directed mutagenesis and chemical modification were used at the same time.