融合淀粉酶AmyP-Clo对大米生淀粉的高效降解

Hydrolysis of raw rice starch by a chimeric α-amylase engineered with α-amylase from Clostridium butyricum T-7

摘要:

[目的]获得能高效降解大米生淀粉的α-淀粉酶。[方法]将来源Clostridium butyricum T-7的α-淀粉酶的淀粉结合结构域与能快速偏好性降解大米生淀粉的α-淀粉酶AmyP的催化结构域融合重组表达。[结果]融合蛋白AmyP-Clo保留了野生型AmyP催化优势的基础上，对大米生淀粉的比活为（373.9±8.4） U/mg，4 h内对5%大米生淀粉的最终降解率为（42.7±1.1）%，对大米生淀粉的最高结合率为（71.1±1.6）%，这些数据相比AmyP分别提高了3.1、2.8和1.3倍。[结论]融合蛋白AmyP-Clo能高效降解生大米淀粉，是一个具有优良应用价值的酶。

关键词:α-淀粉酶;大米生淀粉;融合表达;淀粉结合结构域

Abstract:

[Objective] To obtain efficient raw rice starch-digesting enzymes. [Methods] α-Amylase AmyP can hydrolyze raw rice starch efficiently. We constructed a chimeric α-amylase (AmyP-Clo) by fusion of the catalytic domain of AmyP and a starch binding domain of α-amylase from Clostridium butyricum T-7. [Results] AmyP-Clo retained the advantages of AmyP, and increased catalytic efficiency towards raw rice starch. The specific activity was (373.9±8.4) U/mg. The final hydrolysis degree was (42.7±1.1)% for the hydrolysis of 5% raw rice starch suspension after 4 h. The maximal fraction of bound protein was (71.1±1.6)%. [Conclusion] AmyP-Clo could efficiently hydrolyze raw rice starch.

Key words:α-amylase;raw rice starch;chimeric protein;starch binding domain