(582dx) Refolding of Laccase With Copper-Based Ionic Liquid

Ionic liquids (ILs) are molten salts which are gaining attention as green solvents to replace organic solvent due to their non-volatile and thermal stable properties and low toxicity. Their physicochemical properties such as hydrophobicity, polarity, density can be easily tuned by the combination of cations and anions. Therefore, these advantages of ILs facilitate their applications in many biological processes.
Laccase is one of the representative metallo-enzyme which needs copper as a cofactor. Therefore, the activity and stability of laccase can be enhanced in copper-induced systems. In general, increased refolding yield could also be achieved by enzyme stabilization, during protein refolding process.
In this study, copper salts and copper-based IL was employed to enhance laccase refolding yield. In order to confirm the effect of copper on the refolding of metallo-enzyme, the same refolding process was also carried with lysozyme which is not metallo-enzyme. When CuCl₂ or [EMIM][CuCl₃] were added to the refolding buffer instead of urea, the laccase refolding yield was improved more than 1.5 and 2.7 times, respectively, compared with the conventional refolding buffer containing urea without ILs. However, no additive effect was observed in the refolding of lysozyme which is a non metallo-enzmye. From these results, we can conclude that this copper-based IL was only effective to the refolding process of metallo-enzyme.