PURPOSE: To provide modified IL-6 which is prepared by bonding polyethylene glycol to glycoprotein or polypeptide having IL-6 activity, and of which the thrombopoiesis accelerating activity it is administrated to organism, is improved.
CONSTITUTION: Polyethylene glycol is bonded to glycoprotein or polypeptide having inteleukin 6 (IL-6) activity, preferably human IL-6 having an amino acid sequence of formula I, through the free amino group or free carboxyl group of the amino acid residue of the glycoprotein or polypeptide. The bonding is performed through succinlyl imide ortriazine, and the hydrogen atom of the amino group is preferably substituted with an group of formula II ((n) is 7-600; R1 is 1-3C alkyl), or formula III (R2 is 1-3C alkyl).
KADOYA TOSHIHIKO
KAKIYA MAKOTO
INOUE HIDEO
