Expression and Characterization of Levansucrase from Clostridium acetobutylicum
Expression and Characterization of Levansucrase from Clostridium acetobutylicum
复制标题
丙酮丁醇梭菌左聚蔗糖酶的表达和表征
DOI：
10.1021/acs.jafc.6b05165
复制
发表时间：
2017-02-01
影响因子：
6.1
通讯作者：
An, Yingfeng
中科院分区：
文献类型：
--
作者：
Gao, Song;Qi, Xianghui;An, Yingfeng
克隆了编码左旋糖酶的乙梭菌基因CA-SACB，并在大肠杆菌中表达。 CA-SACB由1287 bp组成，并编码428个氨基酸残基，可以将150 mmol/L蔗糖转换为Levan，并通过葡萄糖释放。该酶的最佳pH和Levan形成的温度分别为pH 6和60度C。 Ca-SACB的余糖酶活性被5 mmol/L ag+和Hg2+完全消除。 K-M和V-MAX，左千非酶的值分别为64 mmol/L和190 Mu mol/min/mg。有趣的是，发现Ca-SACB具有较高的产品特异性，并且在产品中未发现果糖糖类，这表明CA-SACB可能对Levan的工业生产很有价值。此外，CA-SACB是从厌氧细菌中分离出的第一个特征的左旋酶，这对于探索新的酶资源和加深对左旋糖酶催化机制的理解应该很有价值。
The Clostridium acetobutylicum gene Ca-SacB encoding levansucrase was cloned and expressed in Escherichia coli. Ca-SacB is composed of 1287 bp and encodes 428 amino acid residues, which could convert 150 mmol/L sucrose to levan with the liberation of glucose. The optimum pH and temperature of this enzyme for levan formation were pH 6 and 60 degrees C, respectively. Levansucrase activity of Ca-SacB was completely abolished by 5 mmol/L Ag+ and Hg2+. The K-m and V-max, values for levansucrase were calculated to be 64 mmol/L and 190 mu mol/min/mg, respectively. Interestingly, Ca-SacB was found to have high product specificity, and no fructooligosaccharide was identified in the product, indicating that Ca-SacB may be valuable for industrial production of levan. In addition, Ca-SacB is the first characterized levansucrase isolated from an anaerobic bacterium, which should be valuable for exploring new enzyme resources and deepening the understanding of the catalytic mechanisms of levansucrases.