β-Glucosidase Isolated from Soybean Okara Shows Specificity toward Glucosyl Isoflavones

Abstract

A novel beta-glucosidase was isolated from soybean okara in this study. Along with the beta-glucosidase, a considerable basic 7S globulin of soybean was obtained in the initial extraction products. The protein samples pretreated with 130 mM dithiothreitol before the step of CM-Sepharose chromatography could greatly enhance the separation of the targeted beta-glucosidase from the impurities. The purified beta-glucosidase was found to be a monomer estimated to be 75 kDa by SDS-PAGE. The optimal temperature and pH for this beta-glucosidase were 45 degrees C and 4.5, respectively. The activity of this purified beta-glucosidase was completely inhibited by 1 mM Hg(2+) or 10 mM Al(3+) ion, and glucose and mannose also affected the activity. This beta-glucosidase possessed strict specificity toward glucosyl isoflavones but not malonylglucosidic conjugates of isoflavones of soybean. The N-terminal amino acid sequence of the beta-glucosidase was EYLKYKDPKA-, which highly matched that of glycosidases in maize (Zea mays) and wheat (Triticum asetivum).

Study of the mechanism of change in flavonoid composition in the processing of Chrysanthemum morifolium (Ramat.) Tzvel. ‘Boju’

“…6, lane 4). The β -glucosidase isolated from Boju is similar to the β -glucosidase subunit reported by Chiou et al [18].

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Purification and characterization of cyanogenic β-glucosidase from wild apricot (Prunus armeniaca L.)

“…1). Similar results have been reported from other plant β-glucosidase such as those from Prunus avium L. (68 kDa monomer), Plumeria obtusa (60.6 kDa monomer), corn stover (62.4 kDa) [9,10,12], Prunus serotina (52 kDa monomer; [27]), and soy bean okara (75 kDa monomer; [28]). …”

Optimisation of soy flour fermentation parameters to produce β-glucosidase for bioconversion into aglycones

“…These results confirmed the observations of Park et al (2001), verifying that the b-glucosidase from A. oryzae was not efficient for hydrolysing malonyl glucosides, but was effective for hydrolysing glucoside isoflavones. The b-glucosidase extracted from okara (a residue of soybean aqueous extracts) also showed no specificity activity with malonyl forms; however, it was effective for isoflavones glycosidic (Chiou et al, 2010).…”