单酶法合成低分子量右旋糖酐的研究进展

Recent Progress in the synthesis of low molecular weights dextran by one-step method with single enzyme

关键词:  酶法  右旋糖酐蔗糖酶  低分子量右旋糖酐  一步法

Key words:  enzymatic synthesis, dextransucrase, Low molecular weight dextran, one-step

摘要:

低分子量右旋糖酐(LMW)是以蔗糖为底物，由右旋糖酐蔗糖酶（dextransucrase, DSR）催化合成的葡萄糖聚合物，经酸水解/酶水解形成其分子量为10000 ~ 20000 Da的右旋糖酐，广泛应用于医药、食品等行业。本文综述了单酶酶法合成右旋糖酐的研究进展，包括酶法/微生物法生产右旋糖酐的优缺点，酶法合成过程的调控，以及 DSR 的固定化和 DSR 的高效表达，以及DSR的结构、催化机制，和DSR 蛋白质工程对合成低分子量右旋糖酐的研究进展情况，在此基础上本文提出DSR单酶一步法直接合成低分子量葡聚糖是一种值得尝试的选择，借助人工智能技术获得更详细的 DSR 结构信息，在进一步解析 DSR 的结构、功能和催化机理的基础上，对其进行了合理的设计和改进，优化酶学性质，实现单酶法一步法直接合成低分子量右旋糖酐，为生产低分子量右旋糖酐提供了新的理论支持。

Abstract:

Low molecular weight Dextran (LMW) is kind of glucose polymer with a molecular weights of 10000-20000 Da, which is obtained from sucrose catalyzed by dextransucrase（DSR) and dextranase（Dase) , and is widely used in the pharmaceutical and food industries. The direct synthesis of Dextran (LMW) with single-enzyme of DSR by one-step method is more economical than the double-enzyme one. In this paper, the recent progress on enzymatic synthesis of dextran involving the expression of DSR in different host, the regulation of the process of synthesis of LMW, the immobilization of DSR, as well as dextranthree-dimensional structure and catalytic mechanism of DSR were summerized. And the investigation of engineered DSR to the synthesis of LMW dextran, and the difficulties in elucidating the mechanism as well as enhancing the quality of DSR were also discussed. This paper proposes that the more detailed structural information of DSR is to be explored via Artificial Intelligence technology . Based on the further information of the structure, function and catalytic mechanism of DSR , it was rationally designed and modified to optimize the properties , so that the method of one-step direct synthesis of LMW dextran by single enzyme of DSR would become the trend of development in the future, and would provide new theoretical support for the production of low molecular weight Dextran.