A glycoside hydrolase family 31 dextranase with high transglucosylation activity from Flavobacterium johnsoniae |
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Authors: | Yoshifumi Gozu Yuichi Ishizaki Yuhei Hosoyama Takatsugu Miyazaki Atsushi Nishikawa |
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Institution: | Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Fuchu, Japan |
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Abstract: | Glycoside hydrolase family (GH) 31 enzymes exhibit various substrate specificities, although the majority of members are α-glucosidases. Here, we constructed a heterologous expression system of a GH31 enzyme, Fjoh_4430, from Flavobacterium johnsoniae NBRC 14942, using Escherichia coli, and characterized its enzymatic properties. The enzyme hydrolyzed dextran and pullulan to produce isomaltooligosaccharides and isopanose, respectively. When isomaltose was used as a substrate, the enzyme catalyzed disproportionation to form isomaltooligosaccharides. The enzyme also acted, albeit inefficiently, on p-nitrophenyl α-D-glucopyranoside, and p-nitrophenyl α-isomaltoside was the main product of the reaction. In contrast, Fjoh_4430 did not act on trehalose, kojibiose, nigerose, maltose, maltotriose, or soluble starch. The optimal pH and temperature were pH 6.0 and 60 °C, respectively. Our results indicate that Fjoh_4430 is a novel GH31 dextranase with high transglucosylation activity. |
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Keywords: | GH31 dextran isomaltose glucosyltransferase Flavobacterium johnsoniae |
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