title: [Cloning, expression and characterization of beta-glucosidase from Aspergillus fumigatus].
abstract: Exploring new beta-glucosidase genes is of great importance to industrialize beta-glucosidase. The genomes of Aspergillus fumigatus contain a bgl gene, which encodes a 65 kDa putative beta-glucosidase. The bgl gene was cloned into an expression plasmid and transformed to Escherichia coli BL21 (DE3). The bgl was expressed upon induction of Isopropyl beta-D-1-thiogalactopyranoside (IPTG). The recombinant protein was purified by GST-tag affinity chromatography. The purified recombinant Bgl was characterized using Esculin as substrate. The optimum temperature and pH were 45 degrees C and 5.0-6.0, respectively. The K(m) for Esculin was 17.7 mmol/L. The enzyme was stable in the range of pH 4-7. After incubation at 70 degrees C for 2 h, the recombinant Bgl remained 60% of its activity. Metal ions and chemical reagents had different influences on the activity of beta-glucosidase. Ca2+ (1 mmol/L) could increase enzyme activity slightly. On the contrary, the enzyme activity was greatly inhibited by 5 mmol/L Sodium dodecyl sulfate (SDS). Based on our results, the A. fumigatus Bgl was thermostable beta-glucosidase.
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Haomiao
authors.initials: H
authors.lastname: Ouyang
authors.affiliation: Guangxi Key Laboratory of Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Science, Nanning 530007, Guangxi, China.
authors.forename: Ribo
authors.initials: R
authors.lastname: Huang
authors.affiliation: Guangxi Key Laboratory of Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Science, Nanning 530007, Guangxi, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Jin
mesh_terms: D001232:Aspergillus fumigatus / Q000201:enzymology*; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D001617:beta-Glucosidase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D001617:beta-Glucosidase