1.Cloning, expression and characterization of beta-glucosidase from Aspergillus fumigatus.
Yi XIE ; Haomiao OUYANG ; Ribo HUANG ; Dong CHEN ; Cheng JIN
Chinese Journal of Biotechnology 2013;29(9):1245-1253
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.
Aspergillus fumigatus
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enzymology
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Cloning, Molecular
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Enzyme Stability
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Escherichia coli
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genetics
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metabolism
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Recombinant Proteins
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biosynthesis
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genetics
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metabolism
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beta-Glucosidase
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biosynthesis
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genetics
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metabolism