Anhui Key Laboratory of Modern Biomanufacturing, School of Life Sciences, Anhui University, Hefei, 230601, Anhui, People's Republic of China.
Appl Microbiol Biotechnol. 2018 Jan;102(2):743-750. doi: 10.1007/s00253-017-8638-1. Epub 2017 Nov 20.
Recombinant chimeric α-amylase (AmyP-Cr) was constructed by a catalytic core of α-amylase (AmyP) from a marine metagenomic library and a starch-binding domain (SBD) of α-amylase from Cryptococcus sp. S-2. The molecular fusion did not alter optimum pH, optimum temperature, hydrolysis products, and an ability of preferential and rapid degradation towards raw rice starch, but catalytic efficiency and thermostability were remarkably improved compared with those of the wild-type AmyP. AmyP-Cr achieved the final hydrolysis degree of 61.7 ± 1.2% for 10% raw rice starch and 47.3 ± 0.8% for 15% raw rice starch after 4 h at 40 °C with 1.0 U per mg of raw starch. The catalytic efficiency was very high, with 3.6-4.0 times higher than that of AmyP. The enhanced catalytic efficiency was attributed to the better thermostability and the higher adsorption and disruption to raw rice starch caused by SBD. The properties of AmyP-Cr open a new way in terms of a new design of raw rice starch processing.
重组嵌合α-淀粉酶（AmyP-Cr）是通过来自海洋宏基因组文库的α-淀粉酶（AmyP）的催化核心和来自隐球菌属 S-2 的α-淀粉酶的淀粉结合结构域（SBD）构建而成的。分子融合并未改变最适 pH 值、最适温度、水解产物以及对原大米淀粉优先和快速降解的能力，但与野生型 AmyP 相比，催化效率和热稳定性显著提高。AmyP-Cr 在 40°C 下，用 1.0 U 每毫克原淀粉处理 10%的原大米淀粉和 15%的原大米淀粉 4 小时后，最终水解度分别达到 61.7±1.2%和 47.3±0.8%。催化效率非常高，比 AmyP 高 3.6-4.0 倍。增强的催化效率归因于更好的热稳定性以及 SBD 对原大米淀粉更高的吸附和破坏。AmyP-Cr 的这些特性为原大米淀粉加工的新设计开辟了一条新路。
