The use of enzymes as catalysts has become increasingly important in many industrial applications such as food processing, detergents, textiles and organic synthesis. However, a limiting factor for the industrial application of enzymes is their poor operational or long-term stability when exposed to environmental challenges, such as elevated temperatures and pH extremes. To extend the range over which proteins are useful for conducting organic transformations, polymers have been ligated onto proteins. The polymer-protein conjugation strongly affects the properties of the enzyme by potentially improving its activity and stability, and offers a means to modify functions. There are two primary means of attaching polymers to biomolecules; the 'grafting-to' strategy, which pairs reactive end-groups on a preformed polymer with amino acid residues on a protein, and the 'grafting-from' strategy, where a small molecule polymerization initiator or chain-transfer agent has been attached onto a biomolecule, with the polymer grown in situ off the biomolecule’s surface. In this study we modified an industrially important enzyme, lipase by the ‘grafting-from’ method, employing photoinduced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. Polymer-protein conjugates were synthesized using two representative lipases, Candida antarctica lipase B (CalB) and Thermomyces lanuginosa lipase (TL). To study the effects of polymer composition and molecular weight on the enzyme activity a hydrophilic and hydrophobic polymer were grafted at three different polymer lengths. We found a significant impact of polymer composition on enzyme activity with hydrophobic polymer substantially increasing enzyme activity.

Synthesis of lipase polymer hybrids via the grafting-from approach

255th National Meeting (2018)

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