水稻土壤宏基因组中的β-葡萄糖苷酶基因克隆、表达及酶活的研究

CLONE, EXPRESSION AND ACTIVITY OF β-GLUCOSIDASE FROM RICE SOIL METAGENOME

β-葡萄糖苷酶(Ec3.2.1.21)属于糖苷水解酶家族3,它能够水解非还原性末端的β-D葡萄糖苷键,释放出游离的葡萄糖及相应的配基。β-葡萄糖苷酶是纤维素降解中的关键酶,对于可再生资源纤维素的利用具有十分重要的意义。本研究从水稻土壤中分离得到β-葡萄糖苷酶基因pds5,将其克隆到表达载体pET32a(+)中,转化BL21大肠杆菌中,并诱导表达该基因。重组BL21大肠杆菌用IPTG诱导后,所提取的酶蛋白具有β-葡萄糖苷酶的活性,经SDS-PAGE分析,确定其相对分子质量为83 kD。通过控制pH和温度的方法,测得该酶酶活最适pH为7.0,最适温度为37.5℃。

β-glueosidase （EC3.2.l.21） belongs to glycoside hydrolases superfamily 3, which could hydrolyzeβ-D-glueosidie bond and release glueose and corresponding aglueone. β-glueosidase is the key enzyme in cellulose degradation. The β-glucosidase gene was cloned into pET32a （＋） and then build upon an expression carrier in BL21Escherichia coli, and induces the expression of the gene. BL21 recombinantE. coli induced by IPTG, the relative molecular mass of the extracted protein with β-glucosidase activity analyzed by SDS-PAGE analysis is 83kD. Through the control of pH and temperature, the optimum pH of the enzyme activity is 7, the optimum temperature is 37.5℃.