碳水化合物结合域CBM3对外切葡聚糖酶性质的影响  

The effect of carbohydrate binding domain(CBM3)on the properties of exoglucanase

作　　者：胡艳梅 周姗娜 乔琦茗 李华南 江正兵 HU Yanmei;ZHOU Shanna;QIAO Qiming;LI Hua’nan;JIANG Zhengbing(State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences,Hubei University, Wuhan 430062, China)

机构地区：[1]湖北大学生命科学学院,省部共建生物催化与酶工程国家重点实验室,湖北武汉430062

出　　处：《湖北大学学报（自然科学版）》2022年第2期131-136,共6页Journal of Hubei University：Natural Science

基　　金：湖北省技术创新专项(2020BBA056、2019ABA117);湖北省中央领导地方科技发展专项(2018ZYYD034);武汉市科技局应用基础研究(20190207010111496);湖北省教育厅科学技术研究计划青年人才项目(201910701301002)资助。

摘　　要：纤维素酶与底物的可及性是酶水解的主要限制因素之一.碳水化合物结合域(CBM)可以提高纤维素酶与底物的可及性,从而促进纤维素酶的酶促水解.本研究探究外源的CBM对外切葡聚糖酶(CBH)性质的影响.我们将一个外源的CBM3与CBH进行融合,并在毕赤酵母(Pichia pastoris)X33中成功表达,得到了CBM3-CBH和CBH的纯酶.比较两者对于微晶纤维素(Avicel)的结合能力和酶学性质.结果显示CBM3-CBH对Avicel的结合能力比CBH高8%,但是两者对不同底物的催化活性无显著差异.两者的最适反应温度均为60℃,最适反应pH均为6.结果表明,外源的CBM虽然能在一定程度上提高CBH对底物的结合能力,但对CBH的酶学性质没有实质性影响.本研究为探究CBM在纤维素酶催化过程中的作用机制奠定了良好的基础.The accessibility of cellulase to substrate is one of the main limiting factors for enzymatic hydrolysis.Carbohydrate binding domain(CBM)can increase the accessibility of cellulase to substrate,thereby promoting the enzymatic hydrolysis of cellulase.This study explored the influence of exogenous CBM on the properties of exoglucanase(CBH).We fused an exogenous CBM3 with CBH and successfully expressed it in Pichia pastoris X33 to obtain the pure enzyme of CBM3-CBH and CBH.The binding ability to microcrystalline cellulose(Avicel)and the enzymatic properties of the two Enzymes were compared.The result shows that the binding ability of CBM3-CBH to Avicel is 8%higher than that of CBH,but there is no significant difference in the catalytic activity of the different substrates.The optimal reaction temperature of both are 60℃,and the optimal reaction pH are 6.The results show that although exogenous CBM can improve the binding ability of CBH to the substrate in a certain extent,it has no substantial effect on the enzymatic properties of CBH.This research has laid a good foundation for exploring the mechanism of CBM in the process of cellulase catalysis.

关 键 词：碳水化合物结合域 外切葡聚糖酶 催化活性 酶学性质 

分 类 号：Q556[生物学—生物化学] Q789