关键词: TteBglB；6-磷酸-β-葡萄糖苷酶；糖苷水解酶

Abstract:

6-phosphate-β-glucosidase (EC 3.2.1.86), an enzyme catalyzes 6-phosphate-glucoside compounds (such as 6-phosphate-cellobiose, 6-phosphate-cellulose oligosaccharides) to produce 6-phosphate-glucose, plays an important role in carbon utilization for microbes. Thermoanaerobacter tengcongensis MB4, a strain of thermophilic anaerobic microorganism, is an excellent resource for thermo-stable protein. In this study, gene TtebglB was isolated from this strain and then heterologously expressed in E.coli BL21 (DE3). The optimum pH and temperature of TteBglB were pH 6.0 and 70℃, respectively, and the enzyme kept stable at a pH 4~10 at 70℃. Additionally, it was also confirmed that TteBglB belonged to glycosyl hydrolase family 1 (GH1) and could act without Mn2+, Ni2+, Co2+, Fe2+ and other divalent metal ions. Using pNPβG6P as substrate, the values of Km, Kcat, and Vmax for this enzyme was 0.054 mmol/L, 81.47/min and 0.003 992 mmol/min, respectively, and specific activity of the enzyme reached to 18093 U/mg.

Key words: TteBglB, 6-phosphate-β-glucosidase, glycosyl hydrolase