Membrane-bound quinoprotein glucose dehydrogenase from acetic acid bacteria produces lactobionic acid by the oxidation of lactose. Its enzymatic activity on lactose and maltose is much lower than that on D-glucose. For that reason, the activity of the enzyme on disaccharides has been considered low. In this study, we show that the isomaltose-oxidizing activity of acetic acid bacteria is much higher than their lactose-oxidizing activity. In addition to isomaltose, the enzyme oxidized gentiobiose and melibiose to the same extent. According to the characteristics of the isomaltose-oxidizing activity and investigations using dehydrogenase-deficient mutant bacteria, we identified the responsible enzyme as membrane-bound quinoprotein glucose dehydrogenase.Abbreviations: AAB: acetic acid bacteria; m-GDH: membrane-bound quinoprotein glucose dehydrogenase; DCIP: 2,6-dichlorophenolindophenol; DP: degree of polymerization; HPAEC-PAD: high-performance anion-exchange chromatography with pulsed amperometric detection; NMR: nuclear magnetic resonance; TLC: thin layer chromatography; COSY: correlation spectroscopy.

中文翻译：

---

膜结合的奎宁蛋白葡萄糖脱氢酶氧化乙酸细菌氧化异麦芽糖，龙胆二糖和蜜二糖。

来自乙酸细菌的膜结合喹蛋白葡萄糖脱氢酶通过乳糖的氧化产生乳糖酸。它对乳糖和麦芽糖的酶活性远低于对D-葡萄糖的酶活性。因此，认为该酶对二糖的活性低。在这项研究中，我们表明，乙酸细菌的异麦芽糖氧化活性远高于其乳糖氧化活性。除异麦芽糖外，该酶还将龙胆二糖和蜜三糖氧化至相同程度。根据异麦芽糖氧化活性的特点和使用脱氢酶缺陷型突变细菌的研究，我们确定了负责的酶是膜结合的喹蛋白葡萄糖脱氢酶。m-GDH：膜结合喹蛋白葡萄糖脱氢酶；DCIP：2，6-二氯苯酚茚酚；DP：聚合度；HPAEC-PAD：高效阴离子交换色谱，带脉冲安培检测；NMR：核磁共振；TLC：薄层色谱； m / z（MH +）。COSY：相关光谱。