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Properties and applications of β‐glycosidase from Bacteroides thetaiotaomicron that specifically hydrolyses isoflavone glycosides
Author(s) -
Byun DaHye,
Choi HyeJeong,
Lee HyeWon,
Jeon HyeYeon,
Choung WooJae,
Shim JaeHoon
Publication year - 2015
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.12786
Subject(s) - xylobiose , genistin , glycoside , bacteroides thetaiotaomicron , glycoside hydrolase , chemistry , daidzin , aglycone , biochemistry , glycosyl , lactose , enzyme , hydrolysis , beta glucosidase , cellobiose , enzymatic hydrolysis , glycosylation , bacteroides , enzyme assay , biology , stereochemistry , cellulase , bacteria , genistein , daidzein , xylan , genetics , endocrinology
Summary To modify the glycan part of glycosides, the gene encoding β‐glycosidase was cloned from Bacteroides thetaiotaomicron VPI‐5482. The cloned gene, bt_1780 , was expressed in Escherichia coli MC1061 and the expressed enzyme was purified using Ni‐NTA affinity chromatography. The purified enzyme, BTBG, showed optimal activity at 50 °C and pH 5.5. Interestingly, this enzyme did not have any hydrolysing activity on ordinary β‐linkage–containing substrates such as xylobiose, lactose and cello‐oligosaccharide, but specifically hydrolysed isoflavone glycosides such as daidzin, genistin and glycitin. Compared to a commercial beta glucosidase, BTBG selectively hydrolysed isoflavone glycosides in soybean extract mixture solution. These results suggest that BTBG may be a specialized enzyme for the hydrolysis of glycosides and that the substrate specificity of BTBG is applicable for the bioconversion of isoflavone glycosides in the food industry.