Facile Enzymatic Transformation of 4² -O-β-D-Galactosylmaltose into 4² -O-β-D-Galactosylmaltobionolactone as a Substrate Analogue Inhibitor for Mammalian α-Amylase

Abstract

Enzymatic transformation of 4² -O-β-D-galactosylmaltose (1) into 4² -O-β-D-galactosylmaltobi-onolactone (2) was carried out by the use of oligosaccharide oxidase (OSOD). The anomer hy-droxyl group of glucose residue at the reducing end of 1 was readily oxidized to the corresponding lactone on a large scale, and the product was conveniently isolated by the sequential column chromatographies of Amberlite IR-120B and Toyopearl HW-405. The desired compound, 2, was obtained in a high yield (80%) based on the addition of 1. The jar-fermentor was included in this reaction system to facilitate the maintenance of pH and supply of air to the reaction mixture. As a result, 2 obtained enzymatically was shown to be identical to that obtained chemically.