A glycoside hydrolase family 31 dextranase with high transglucosylation activity from Flavobacterium johnsoniae
A glycoside hydrolase family 31 dextranase with high transglucosylation activity from Flavobacterium johnsoniae
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DOI：
10.1080/09168451.2016.1182852
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发表时间：
2016-08-01
影响因子：
1.6
通讯作者：
Tonozuka, Takashi
中科院分区：
文献类型：
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作者：
Gozu, Yoshifumi;Ishizaki, Yuichi;Tonozuka, Takashi
糖苷水解酶家族（GH）31酶表现出各种底物特异性，尽管大多数成员是β-葡糖苷酶。在这里，我们构建了一个异源表达系统的GH 31酶，Fjoh_4430，从黄杆菌约氏NBRC 14942，使用大肠杆菌，并表征其酶学性质。该酶水解葡聚糖和普鲁兰多糖，分别产生异麦芽寡糖和异潘糖。以异麦芽糖为底物，酶催化水解生成低聚异麦芽糖。该酶也作用于对硝基苯基-D-吡喃葡萄糖苷，但效率不高，并且对硝基苯基-异麦芽糖苷是反应的主要产物。相反，Fjoh_4430不作用于海藻糖、曲二糖、黑曲霉糖、麦芽糖、麦芽三糖或可溶性淀粉。最适pH为6.0，最适温度为60 ℃。我们的研究结果表明，Fjoh_4430是一种新的GH 31葡聚糖酶，具有高转葡萄糖基化活性。
Glycoside hydrolase family (GH) 31 enzymes exhibit various substrate specificities, although the majority of members are -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 -D-glucopyranoside, and p-nitrophenyl -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 pH6.0 and 60 degrees C, respectively. Our results indicate that Fjoh_4430 is a novel GH31 dextranase with high transglucosylation activity.