99A-35 |
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N.-Y. PARK1, K.-S. Kim1, K.-H. Park2, M.-Y. Baik1, and C.-S. Park1. (1) Department of Food Science and Technology, KyungHee University, 1 Seocheon-ri, Kiheung, Yongin, 449-701, South Korea, (2) Department of Food Science and Technology, Seoul National University, School of Agricultural Biotechnology, San 56-1, Silim-dong, Kwanak-gu, Seoul, 151-742, South Korea Consumption of soy-based foods is associated with as a number of health benefits, including lower risk of cardiovascular disease, breast and prostate cancer, attenuated menopausal symptoms, and prevention of bone loss with age. Isoflavones are found mainly in soybeans and kudzu roots as glycosides. However, effective adsorption of the isoflavones likely requires the conversion of glycosides to aglycones via the action of b-glycosidase. b-glycosidase from Sulfolobus sofataricus, a hyperthermophilc archaea, is particular attractive for the biotechnological applications by offering high enzymatic stability in various conditions such as pH, temperature, and organic solvents. The objective of this study was to express the b-glycosidase of Sulfolobus sofataricus in E. coli, and to apply the recombinant b-glycosidase to convert isoflavone glycosides of soybean and kudzu roots into their aglycones. The gene corresponding to b-glycosidase from the archeon Sulfolobus sofataricus has been obtained PCR. The b-glycosidase gene was overexpressed with the expression vector p6XHis119 in E. coli. The transform of isoflavone glycosides into its aglycones was detected by TLC and HPLC analyses. The b-glycosidase gene of the archeon Sulfolobus sofataricus was successfully expressed in E. coli. The recombinant enzyme was highly thermostable by showing its optimal temperature of 75°ĘC and pH 5. The enzyme was reacted with the crude extract of soybean and kudzu roots at 60°ĘC. The TLC and HPLC analyses showed that the isoflavone glycosides (genistin and daidzin) in both soybean and kudzu roots were efficiently converted (more than 90%) into their aglycone forms (genistein and daidzein). This result showed that the possible application of the recombinant enzyme obtained from hyperthermophilic archeon on the deglycosylation of plant isoflavones. By this enzymatic transformation, various plant isoflavone glycosides can be converted into its aglycones which maybe more effective adsorption form in human body.
Session 99A, Biotechnology: General
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