Enzymatic Synthesis of a New Derivative of Thiamin, O-α-Glucosylthiamin

抄録

  A new transglucosylated derivative of thiamin could be synthesized by the actions of cyclomaltodextrin glucanotransferase from Bacillus stearothermophilus and glucoamylase from Rhizopus sp., in this order, on a mixture of dextrin and thiamin. The derivative was isolated in crystalline form and identified as 5′-O-(α-D-glucopyranosyl)thiamin by spectroscopy (FAB-MS, UV, ¹H-NMR, and ¹³C-NMR), thiochrome formation with K₃ [Fe(CN)₆]-NaOH reagent, and the hydrolysis products by α- and β-glucosidases. O-α-Glucosylthiamin was odorless and mildly sweet with no tongue-pricking taste, and was more stable than thiamin hydrochloride in aqueous solutions at pHs 7.0 and 9.3.