Transglucosylation of hydroquinone catalysed by alpha-glucosidase from baker's yeast

Abstract

Hydroquinone alpha-isomaltoside and hydroquinone alpha-glucoside were synthesized by transglucosylation in an aqueous system with baker's yeast alpha-glucosidase from hydroquinone and maltose as a glucosyl donor. Only one phenolic group was glucosylated, with alpha-selectivity, and the nature of the reaction products was governed by the concentration of hydroquinone. The optimal conditions for synthesis of glycosides were 9 mM hydroquinone and 1.5 M maltose in a 100 mM sodium citrate/phosphate buffer at pH 5.0 and 30 degrees C for 20 h. Under these conditions both hydroquinone alpha-glycosides were obtained in nearly equimolar amounts with a total molar yield of 28% with respect to hydroquinone and a total glycoside concentration of 1 mg/mL in the reaction mixture. (c) 2005 Elsevier B.V. All rights reserved.