MUTANT OF GRANULOCYTE-COLONY STIMULATING FACTOR(G-CSF) AND CHEMICALLY CONJUGATED POLYPEPTIDE THEREOF

A mutant of granulocyte-colony stimulating factor(G-CSF) and a chemically conjugated polypeptide thereof are provided to increase the retention time of G-CSF in human body without reduction of biological activity by introducing cysteine into the G-CSF, so that in vivo activity of G-CSF is maintained for a long period of time. The mutant of granulocyte-colony stimulating factor(G-CSF) having the amino acid sequence of SEQ ID NO:3 is produced by substituting a 133th threonine residue of human granulocyte-colony stimulating factor(G-CSF) having the amino acid sequence of SEQ ID NO:1 for a cysteine residue. The chemically conjugated polypeptide of granulocyte-colony stimulating factor(G-CSF) mutant is produced by modifying a biocompatible polymer to the substituted cysteine residue of the granulocyte-colony stimulating factor(G-CSF) mutant, wherein the biocompatible polymer is composed of one compound selected from polyethyleneglycol(PEG), polyvinylalcohol(PVA), polycarboxylic acid or polyvinylpyrrolidone binding to one compound selected from maleimide, vinyl sulfone, iodoacetamide and orthopyridyl disulfide.