β-环糊精葡萄糖基转移酶突变基因的表达及突变酶酶学性质分析  

Study on mutant gene expression of β- CGTase and its enzymology characteristics analysis

作　　者：王华[1] 李华[1] 

机构地区：[1]内蒙古民族大学生命科学学院,内蒙古通辽028000

出　　处：《食品工业科技》2015年第13期180-183,188,共5页Science and Technology of Food Industry

基　　金：内蒙古民族大学国培项目(NMDGP1413)

摘　　要：通过对已构建的β-CGTase质粒载体采用一步PCR法进行大片段基因的定点突变,得到三个带有突变位点的质粒载体,并将其进行转化得到突变菌株。分析突变酶的酶学性质并与β-环糊精葡萄糖基转移酶比较,结果表明突变酶酶活力提高到原酶活力的1.6倍以上,且突变酶作用的最适温度60℃、最适p H6.0、在60℃下和p H5~8范围内均非常稳定,经方差分析突变酶与原酶的酶学性质差异不显著（p〉0.05）,但是酶活力差异显著（p〈0.05）。Using one-step PCR, three amino acid residues Y127, R254 and D355 within the conserved protein domain of β-cyclodextrin glucosyl transferase were subjected to site-directed mutagenesis, and the mutant plasmids were transformed into Escherichia coil BL21 （ DE3 ） for effective expression, respectively. The result showed that the activity of mutant enzymes was 1.6 times higher than initial enzyme.The mutant enzymes were optimal at 60℃ and pH6.0, and that the enzymes were stable for at least 60min at 60% and across a wide pH5.0- 8.0, the enzymatic properties existed no significant difference among mutant enzymes and initial enzyme （p 〉0.05）,but there existed significant difference about activity between mutant enzymes and initial enzyme （p 〈0.05）.

关 键 词：β-环糊精葡糖糖基转移酶 定点突变 环化活性 温度 p H 

分 类 号：TS202.3[轻工技术与工程—食品科学]