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

【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Amy P的催化结构域融合重组表达。【结果】融合蛋白Amy P-Clo保留了野生型Amy P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Amy P分别提高了3.1、2.8和1.3倍。【结论】融合蛋白Amy P-Clo能高效降解生大米淀粉,是一个具有优良应用价值的酶。

[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.