腊样芽孢杆菌低温淀粉酶基因的克隆表达及酶学性质研究  

Cloning, expression and enzymatic properties of cold-adapted amylase from Bacillus cereus

作　　者：师永生[1] 谢建华[1] 吴磊[1] 杜丽琴[1] 黄日波[1] 韦宇拓[1] 

机构地区：[1]广西大学 广西亚热带生物资源保护利用重点实验室,广西南宁530005

出　　处：《工业微生物》2011年第2期32-36,共5页Industrial Microbiology

基　　金：国家"863"项目(No.2006AA020204)资助

摘　　要：从废弃的淀粉堆中筛选到一株产低温淀粉酶的蜡样芽孢杆菌(Bacillus cereus)GXBC-1,通过同源保守序列比对,从中克隆到一个淀粉酶基因。该基因全长为1 764 bp,编码588个氨基酸,分子量约为64kD。将基因克隆到大肠杆菌进行表达及酶学性质研究,该重组酶最适温度为35℃,在20℃仍具有53%的活力;最适pH值为7.0,Km值为0.72 mg/mL。产物经HPLC分析,该酶没有内切酶活性,具有典型的β-淀粉酶特性。A cold-adapted amylase-generated bacterium GXBC-1 was isolated from starch-pile by dilution method, which was preliminarily identified as Bacillus cereus. GXBC-1. Amylase gene was amplified by polymerase chain reaction （PCR）. Nucleotide sequence analysis showed that the amyGXBC-1 gene was composed of I 764 bp （588 amino acid residues with Mw of 64 kD）. The characteristics of the cold-adapted amylase were also discussed . The optimum temperature for the amylase was 35℃ and the optimum pH was 7.0. Even at 20℃, the enzyme still showed 53 % enzyme activity. But the amylase was not stable above 50℃. Its Km was 0.72 mg/mL. The results of HPLC of products from starch demonstrated that this enzyme, without the activity of incision enzyme, should be classified as β-amylase.

关 键 词：腊样芽孢杆菌 低温淀粉酶 克隆表达 酶学性质 

分 类 号：Q78[生物学—分子生物学] TQ925.1[轻工技术与工程—发酵工程]