… with polyethylene glycol monomethyl ether. Pegylation occurs at one lysine residue at position 31, 121, 131 or … with polyethylene glycol monomethyl ether. Pegylation occurs at one nitrogen atom of either the cysteine residue … a form of filgrastim (INN) (a human granulocyte colony-stimulating factor (G-CSF)) of sustained …