Preparation of Protein-Polymer Conjugates: Copolymerisation by RAFT

A method for the preparation of protein-polymer conjugates is presented that represents a different approach to current conjugation techniques. A protein-polymer conjugate was prepared by reversible addition-fragmentation chain-transfer (RAFT) copolymerisation, where one of the species of monomer used contains a protein. The enzyme horseradish peroxidase (HRP) was functionalised with an acrylate group via a polyethylene glycol (PEG) linker to the protein surface lysine residues. The PEG linker promoted aqueous solubility of the acrylate group, which led to an improved yield of HRP functionalisation. RAFT copolymerisation with N-acryloylmorpholine (NAM) resulted in synthesis of an HRP-RAFT copolymer, with full retention of the enzyme's activity.