BETA-GLUCOSIDASES FROM SOYBEANS HYDROLYZE DAIDZIN AND GENISTIN

Beta-glucosidases which hydrolyze isoflavone glucosides, daidzin and genistin, were partially purified from soybean cotyledon. Three isoforms of beta-glucosidases (A,B,C) were separated on a CM-Sephadex C-50 ion exchange column. Beta-glucosidase-B and C brought about nearly all of the hydrolyzing action on daidzin and genistin. Beta-glucosidase-B and C were further purified with gel-filtration chromatography, and the partially purified enzymes were characterized at pH 5.0 and 45-degrees-C, (optimum conditions). Adding the beta-glucosidase-B and C to soymilk at 45-degrees-C, both enzymes hydrolyzed daidzin and genistin and caused an increase in aglycones daidzein and genistein.