NOVEL CONJUGATED PROTEINS AND PEPTIDES

The invention provides a novel process for conjugating a polymer, especially PEG, to a protein or peptide, which comprises reacting a polymeric conjugation reagent with a protein or peptide containing a polyhistidine tag under conditions such that conjugation occurs via said polyhistidine tag. The resulting conjugates are novel. The invention further relates to novel conjugates of the general formula (I) in which one of X and X′ represents a polymer, and the other represents a hydrogen atom; each Q independently represents a linking group; W represents an electron-withdrawing moiety or a moiety preparable by reduction of an electron-withdrawing moiety; or, if X′ represents a polymer, X-Q-W- together may represent an electron withdrawing group; and in addition, if X represents a polymer, X′ and electron withdrawing group W together with the interjacent atoms may form a ring; Z represents a protein or a peptide linked to A and B via respective histidine residues; A is a C1-5 alkylene or alkenylene chain; and B is a bond or a C1-4 alkylene or alkenylene chain.