作　　者： ; ; ; ; ; ;

机构地区： 广西大学生命科学与技术学院广西亚热带生物资源保护利用重点实验室

出　　处： 《工业微生物》 2011年第2期32-36,共5页

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

领　　域： [生物学]