β‐Glucosidases from Soybeans Hydrolyze Daidzin and Genistin

ABSTRACT β‐Glucosidases which hydrolyze isoflavone glucosides, daidzin and genistin, were partially purified from soybean cotyledon. Three iso‐forms of β‐glucosidases (A,B,C) were separated on a CM‐Sephadex C‐50 ion exchange column. β‐Glucosidase‐B and C brought about nearly all of the hydrolyzing action on daidzin and genistin. β‐Glu‐cosidase‐B and C were further purified with gel‐filtration chromatog‐raphy, and the partially purified enzymes were characterized at pH 5.0 and 45°C, (optimum conditions). Adding the β‐glucosidase‐B and C to soymilk at 45°C, both enzymes hydrolyzed daidzin and genistin and caused an increase in aglycones daidzein and genistein.