Enzymatic Formation of a New Derivative of Thiamin,<i>β</i>-Galactosylthiamin

Abstract

A new derivative of thiamin, glycosylated thiamin, was found to be formed from o-nitrophenyl β-d-galactopyranoside and thiamin in 33% CH3CN by Aspergillus oryzae β-galactosidase. The derivative was isolated in a crystalline form from the reaction mixture by a procedure including PPC, activated vitachange column chromatography, ethanol treatment, PPC, gel-filtration on Toyopearl HW-40S, and lyophilization, and identified as 5′-O-(β-d-galactopyranosyl)-thiamin on the basis of various experimental results, viz., FAB-MS, UV, IR, 1H-, and 13C-NMR spectra, thiochrome formation with K3[Fe(CN)6]-NaOH reagent, and products by hydrolysis with α- and β-galactosidases. Ο-β-Galactosylthiamin was odorless and mildly sweet with no stimulative tongue-pricking taste.