Abstract
Pure crystals (mp 273_??_274°C, decomp.) of 12.2mg riboflavin-β-glucoside were obtained from the mixture (2.8 liter) containing 150g cellobiose, 1.2g riboflavin and 1.4 liter of 0.1M acetate buffer (pH 5.3) with 200ml commercial β-glucosidase (2g) prepared from almond, after the incubation at 37°C for 8hr in the dark. Pure crystals were identified as riboflavin-β-glucoside, by comparison of the properties of the crystals, viz., Rf values, absorbance at 220 to 500mμ, and products by hydrolysis with HCl or with β-glucosidase, with those of the crystalline 5'-D-riboflavin-β-D-glucopyranoside synthesized by enzyme preparations from plant grains. With 500mg of the same β-glucosidase, 5.4mg riboflavin-β-galactoside was isolated from incubated mixture of 300mg riboflavin and 37.5g lactose. When β-glucosidase ((NH4)2SO4 fraction of 50_??_75% saturation) was submitted to disc electrophoreses at pH 4.0, 6.6 and 8.0, both β-glucosidase activity and riboflavin-β-glucoside-forming activity were detected in the same section of unstained gel.
