多粘芽孢杆菌(Bacillus polymyxa)β-葡萄糖苷酶基因在大肠杆菌中的表达、纯化及酶学性质分析

从多粘芽孢杆菌(Bacillus polymyxa1．794)中克隆得到β—葡萄糖苷酶基因bglA。将其构建在大肠杆菌(Escherichia coli)表达载体pET28a( )上，转化E．coli BL21，获得重组工程菌BL1979。重组表达的β—葡萄糖苷酶的酶活力达到24．7IU／mL，经镍柱纯化后的β—葡萄糖苷酶最适温度为37℃，最适pH值为7．0，该酶经纯化后纯度可达92．7％。用非变性梯度聚丙烯凝胶电泳发现该酶具有多种寡聚体形式，经荧光底物活性染色表明这些寡聚体均具有β—葡萄糖苷酶活性。

Expression,Purification and Enzymatic Characterization of Bacillus polymyxa β-glucosidase Gene(bglA)in Escherichia coli

The beta-glucosidase encoding gene bglA was cloned from Bacillus polymyxa 1.794. The bglA gene was inserted in expression vector pET28a(+) and transformed into Escherichia coli BL21 (DE3), finally the recombinant strain BL1979 was obtained. Induced by IPTG, the expression P-glucosidase activity reached to 24.7 IU/mL. The optimum temperature and optimum pH of the recombinant expression P-glucosidase in BL1979 were 37 degrees C and 7.0 respectively,the purity can reach to 92.7%. Analysis of the fusion protein by nondenaturing gradient gel electrophoresis, we found the fusion protein exists in dimmer, tetramer,hexamer and octamer, they all have hydrolase activity.