Patent ID: 8859731

Claim:
A method of selectively introducing a substituent (G) into a Factor VIII protein proximal to a binding site on the protein for a homing peptide (P), the method comprising: (a) contacting the Factor VIII protein with a targeted reagent comprising a compound represented by formula (I): wherein: P is a homing peptide comprising 5-15 amino acids, L is a linker, X is a direct bond or NH, G is G1 or G2, wherein G1 comprises a functional group and G2 is a substituent that is capable of increasing the plasma half-life of the target protein, and q is an integer of from 1 to 9 wherein each G is the same or different if q is greater than 1; and (b) allowing a moiety on the protein proximal to the binding site to react with the targeted reagent, thereby to transfer the substituent G onto the protein via transfer of an acyl group from an ester group present in the targeted reagent to the protein.