β-Glucosidase Isolated from Soybean Okara Shows Specificity toward Glucosyl Isoflavones
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- 作者：Tai-Ying Chiou ; Yi-Hsuan Lin ; Nan-Wei Su ; Min-Hsiung Lee
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2010
- 出版时间：August 11, 2010
- 年：2010
- 卷：58
- 期：15
- 页码：8872-8878
- 全文大小：838K
- 年卷期：v.58,no.15(August 11, 2010)
- ISSN：1520-5118
文摘
A novel β-glucosidase was isolated from soybean okara in this study. Along with the β-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 β-glucosidase from the impurities. The purified β-glucosidase was found to be a monomer estimated to be 75 kDa by SDS−PAGE. The optimal temperature and pH for this β-glucosidase were 45 °C and 4.5, respectively. The activity of this purified β-glucosidase was completely inhibited by 1 mM Hg2+ or 10 mM Al3+ ion, and glucose and mannose also affected the activity. This β-glucosidase possessed strict specificity toward glucosyl isoflavones but not malonylglucosidic conjugates of isoflavones of soybean. The N-terminal amino acid sequence of the β-glucosidase was EYLKYKDPKA-, which highly matched that of glycosidases in maize (Zea mays) and wheat (Triticum asetivum).