Activation and stabilization of a lipase nanogel using GMA for acryloylation

Abstract

A lipase nanogel has been prepared by aqueous in situ polymerization, with initial acryloylation to introduce vinyl groups onto the lipase surface for subsequent polymerization with acrylamide monomers. Activation of lipase was observed using glycidyl methacrylate (GMA) as the acryloylation agent, leading to an increase of activity yield from 78 ± 4% (obtained using NAS for acryloylation) to 122 ± 14%. The acryloylation ratio was also improved, from 8 ± 5% to 20 ± 8%, which favored the subsequent polymerization. In addition, the overall activity yield of the lipase nanogel was increased from 44 ± 3% to 105 ± 2%. The lipase nanogel prepared with GMA for acryloylation displayed a lower K_m and a higher k_cat in comparison to its native counterpart, as well as the nanogel obtained using NAS for acryloylation. The half-life of the lipase nanogel at 60 °C was extended from 1.63 h (using NAS for acryloylation) to 5.61 h, while the half-life of the native lipase was 1.41 h. Molecular dynamics simulations and experiments further suggested that the activation effect was due in part to interactions between the lipase and the GMA, which reinforced the ‘open’ configuration of the lipase, thereby facilitating mass transport to and from the modified lipase in the free and encapsulated forms. The above mentioned activation effect of the enzyme nanogel illustrated the power of chemical modification by tailored design of the nanostructure of the enzyme catalyst, potentially expanding the applications of enzyme catalysis.