马奶酒样乳杆菌乳糖酶LacZ基因的克隆,原核表达及活性分析  

Cloning,expression and characterization of LacZ gene from Lactobacillus kefiranofaciens

作　　者：何熹[1,2] 耿伟涛[1] 韩宁[2] 王艳萍[1] 

机构地区：[1]天津科技大学食品工程与生物技术学院,天津300457 [2]齐鲁工业大学生物工程学院,山东济南250353

出　　处：《食品与发酵工业》2016年第4期28-31,共4页Food and Fermentation Industries

摘　　要：从开菲尔粒（Kefir）中分离出1株马奶酒样乳杆菌（Lactobacillus kefiranofaciens ZW3）,具有较高的乳糖酶活性,以此菌株为材料,从其基因组中克隆得到LacZ型乳糖酶基因,该基因全长2007 bp,编码669个氨基酸。随后将该基因插入原核表达载体pET-32a中转入大肠杆菌BL21（DE3）进行过量表达,获得了其重组蛋白,纯化后分析了该重组蛋白的乳糖水解活性特点。结果显示,此蛋白在50℃,pH 7.0时乳糖水解活力最高,并在30-55℃,pH 5.0-9.0的范围仍能保持50%以上的酶活力,具有良好的工业应用潜力。A Lactobacillus kefiranofaciens ZW3 with high lactase activity was isolated from Kefir in our laboratory.Using Lactobacillus kefiranofaciens ZW3 as material,a LacZ type of lactase gene was cloned from ZW3 genome,and the full-length of this gene encoding 669 amino acids was 2007 bp. The gene was then inserted into the p ET-32 a vector and transformed into E. coli BL21（ DE3）. The lactose hydrolysis activity of this recombinant protein was analyzed after purification. The results showed that the optimum temperature and p H for hydrolyzation of the recombinant protein was 50 ℃,p H 7. 0. In the range of 30 - 55 ℃ and p H 5. 0 - 9. 0,the recombinant protein still maintained more than 50% of the enzyme activity,which exhibited a good potential for industrial applications.

关 键 词：Β-半乳糖苷酶 基因克隆 原核表达 

分 类 号：Q78[生物学—分子生物学]