Effective transgalactosylation catalysed by a lipid-coated β-D-galactosidase in organic solvents

Abstract

A lipid-coated β-D-galactosidase was prepared, which was soluble in most organic solvents such as diisopropyl ether, 2,2,4-trimethylpentane and benzene, but insoluble in aqueous solution. It could act as an efficient transgalactosylation catalyst for various hydrophobic alcohols with p-nitrophenyl β-D-galactopyranoside in dry diisopropyl ether. When a native β-D-galactosidase was used in aqueous solution containing acetonitrile for the same reaction, the yield of the transgalactosylation was low due to the predominant process of hydrolysis. The enzyme activity for the galactosylation depended on coating lipid molecules, the origin of the enzyme used, the reaction's organic solvents and the chemical structures of the acceptor alcohols.