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Properties of a metagenome-derived beta-glucosidase from the contents of rabbit cecum

In this study, a previously cloned β-glucosidase gene, umbgl3B, was heterologously expressed in Escherichia coli, and the biochemical properties of the purified enzyme were characterized. The recombinant enzyme was stable over a wide range of pH values (5.0-9.0) and below 30 °C. It displayed optimum...

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Bibliographic Details
Published in:Bioscience, biotechnology, and biochemistry biotechnology, and biochemistry, 2009-07, Vol.73 (7), p.1470-1473
Main Authors: Feng, Y.(Guangxi Univ., Nanning (China)), Duan, C.J, Liu, L, Tang, J.L, Feng, J.X
Format: Article
Language:English
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Summary:In this study, a previously cloned β-glucosidase gene, umbgl3B, was heterologously expressed in Escherichia coli, and the biochemical properties of the purified enzyme were characterized. The recombinant enzyme was stable over a wide range of pH values (5.0-9.0) and below 30 °C. It displayed optimum enzymatic activity at pH 6.5 at 40 °C, under condition similar to that in the rabbit cecum, suggesting an active role of the native enzyme in vivo. The recombinant β-glucosidase Umbgl3B showed high activity to aryl β-D-glucosides and low activity to cellooligosaccharides, with a polymerization degree of less than 5. The enzyme had no activity toward long cellooligosaccharides or polysaccharides. The aspartic acid residue, D772, of the wild-type Umbgl3B was predicted as a nucleophile. Mutant D772A was constructed. It showed less than 1/10,000 activity of the wild-type enzyme, but had the same properties, suggesting that residue D772 plays a key role in the enzyme's activity.
ISSN:0916-8451
1347-6947
DOI:10.1271/bbb.80664