具有大豆异黄酮水解活性的β-葡萄糖苷酶的纯化和特性（英文）  

Purification and Characterization of an Extracellular β-glucosidase involved in Hydrolysis of Soybean Isoflavone from Bacillus korlensis ZF-6C

作　　者：刘颖[1] 曹小芳[2] 郑芳[2] 李振鹏[1] 白钢[2] 白芳[1,2] 

机构地区：[1]南开大学药物化学生物学国家重点实验室,生命科学学院 [2]南开大学分子药物研究天津重点实验室,药学院,天津300071

出　　处：《南开大学学报（自然科学版）》2017年第2期91-101,共11页Acta Scientiarum Naturalium Universitatis Nankaiensis

基　　金：Supported by the Tianjin Municipal Science and Technology Commission,China(14JCYB JC28500)

摘　　要：葡萄糖苷酶(β-Glucosidase,EC 3.2.1.21)可以催化水解芳香基与糖基之间的糖苷键,被广泛应用于食品工业中对天然活性产物的加工、增效.本研究从一株芽孢杆菌的发酵液中,分离得到了一种具有β葡萄糖苷酶活性的胞外酶,命名为Fbg A.该酶以单体形式存在,分子量约为83 k Da,在p H7.0和40℃条件下酶活性最高,该酶在其最适反应条件下可持续工作近1个月的时间.酶学动力学分析表明,Fbg A可专一性水解芳基葡萄糖苷中的β(1,4)糖苷键,对大豆异黄酮的两种主要活性成分染料木苷(Genistin)和大豆苷(Daidzin)具有高亲和性,其米氏常数(Km值)分别为0.34和1.99 mol/L.利用高效液相色谱检测到,Fbg A(31 U/m L)可在3 h内,将大豆粉提取物中1.03 mmol/L的染料木苷和0.86 mmol/L的大豆苷完全水解为更易被人体吸收的苷元形式,对应的生产率分别为0.50和0.33 mmol/Lh.Fbg A较高的大豆异黄酮水解活性和良好的酶活力稳定性使其具有可应用于食品工业中的豆制品加工的潜力.An extracellular β-glucosidase activity was isolated and purified from the fermentation broth of Bacillus korlensis strain ZF-6C. The native enzyme, designated FbgA, existed as a 83 kDa monomer with an maximum activity at pH 7.0 and 40 ℃. Under this optimal reaction condition, the activities of FbgA could be maintained for almost one month, The enzymatic kinetic assays suggest that FbgA has high hydrolytic activity against two main soybean isoflavone components： genistin （Kin of 0.34 mmol/L） and daidzin （Km of 1.99 mmol/L）. In the soybean flour extract, 1.03 mmol/L genistin and 0.86 mmol/L daidzin were completely hydrolyzed within 120 and 180 min, corresponding to productivities of 0.50 and 0.33 mmol/Lh, respectively. Partial amino acid sequences of FbgA were identified and showed high homology with glycoside hydrolase family 3 （GH3） β-glucosidase, indicating FbgA was probably a GH3 β-glucosi- dase from B. korlensis with hydrolytic activities of soybean isoflavones.

关 键 词：Β-葡萄糖苷酶 蛋白质分离纯化 酶学性质 大豆异黄酮 

分 类 号：Q939.97[生物学—微生物学]