β-环糊精葡萄糖基转移酶的固定化及其酶学性质

Immobilization and Enzymatic Property ofβ-cyclodextrin Glycosyltranserase

采用吸附-交联法对β-环糊精葡萄糖基转移酶(β-cyclodextrin glycosyltranserase,β-CGTase)进行固定化,对吸附载体进行了比较和筛选,优化了交联条件,并对固定化后酶的催化特性进行了初步分析。研究表明阴离子交换树脂D380对β-CGTase的吸附性较好;固定化的最佳条件为:戊二醛浓度0.02%、pH 8.0、4℃和固定化8 h,固定化后β-CGTase的酶活可达842 U/g。固定化β-CGTase的热稳定性显著提高,具有良好的操作稳定性;与游离态相比,固定化β-CGTase催化瑞鲍迪苷A形成的产物较少,显现出更佳的催化特异性。

β-cyclodextrin glycosyltranserase(β-CGTase)was immobilized by the method of adsorption-crosslinking,during which the adsorption vector was compared and screened,the crosslinking conditions were optimized and the catalytic properties of the immobilized enzyme were analyzed.The results showed that the anion-exchange adsorption resin(D380)had a good adsorbability forβ-CGTase.The optimal immobilization conditions were as follows:glutaraldehyde concentration was 0.02%,pH=8.0,with 4℃and 8 h.The activity of immobilizedβ-CGTase reached 842 U/g.The thermal stability of immobilizedβ-CGTase was improved significantly,and the operation stability was good.As compared with the freeβ-CGTase,the formed products were fewer when rebaudine A was catalyzed by the immobilizedβ-CGTase,which showed the better catalytic specificity.