关键词: &alpha, -半乳糖苷酶, 短状杆菌, 基因克隆, 表达, 性质

Abstract: Alpha- galactosidase is a kind of industrial enzyme preparation with a huge commercial value, which has been widely used in medicine, food and chemical industries. A strain of Brachybacterium sp. DB5 was selected to isolate α- galactosidase gene by PCR. Sequencing and BLAST analysises showed that the sequence encoded a α-galactosidase. It was recombinant into the vector pET-30a(+) and transformed into the strain E. coli. α-Galactosidase gene was expressed efficiently after induction with IPTG. An expression activity 5.07 U/mL was obtained. After purification of pure, enzyme activity was 72.78 U/mL. The enzymatic analysis revealed that its optimal pH and temperature were 6.0 and 40℃, respectively. The enzyme could be used for additive of animal feed, soybean meal, in order to improve the feed utilization rate.

Key words: α-galactosidase, Brachybacterium sp., gene cloning, expression, characterization