Characterization of polymer–enzyme complex as a novel biocatalyst for nonaqueous enzymology

Abstract

The optimal methodology to prepare the novel modified enzyme, polymer–enzyme complex, was developed to give a high catalytic activity in anhydrous organic media. The complex was prepared by mixing an enzyme and various polymers in various buffer solutions, and subsequently lyophilizing them. Optimal preparation conditions were obtained when poly(ethylene glycol) (PEG) 4000 was used as a modifier of α-chymotrypsin for the transesterification of Ac- l-PheOEt and 1-propanol in anhydrous isooctane. Additionally, we found that poly(ethylene glycol) and poly(vinyl pyrrolidone) gave a polymer–enzyme complex that had a high catalytic activity in organic media. This strongly suggested that the amphiphilic nature of polymers was important to prepare the polymer–enzyme complex in an aqueous buffer solution, and subsequently used in an organic media. We finally succeeded in preparing the poly(vinyl pyrrolidone)–α-chymotrypsin complex which showed ca. 15,000-fold higher activity than native α-chymotrypsin in anhydrous isooctane under the same preparation conditions.