Functionnal Characters of Alcohol and Methanol Dehydrogenases in the Respiratory Chain of Acetic Acid Bacteria

甲醇酸乙酸杆菌是一种独特的醋酸菌，它除了乙醇氧化酶呼吸链外，还具有甲醇氧化酶呼吸链，如在甲基营养菌中所见。本研究探讨了甲醇和乙醇氧化酶呼吸链之间的关系。此外，本研究还对甲氧西林拟青霉的甲醇脱氢酶(MDH)和甲壳拟青霉等几种醋酸菌的乙醇脱氢酶(ADH)的结构和功能进行了研究。(1)以甲醇为底物的甲醇曲霉表现出较高的甲醇氧化酶活性，且含有细胞色素c氧化酶细胞色素co，而以甘油为底物的细胞则表现出较高的乙醇氧化酶活性，且含有泛喹酚氧化酶细胞色素bO。本研究的结果表明，甲醇菌对甲醇和乙醇有两条独立的呼吸链。甲醇氧化酶呼吸链似乎是通过将mdh连接到细胞色素c氧化酶…来运作的。更多的细胞色素co，通过可溶性细胞色素(S)c，而乙醇氧化酶呼吸链由ADH、泛醌和细胞色素bO泛喹酚氧化酶组成。(2)从甲醇培养的甲醇曲霉中分离纯化出两种不同类型的MDH。其中一个有α2Gamma2结构，而另一个有alpha2Gamma2结构。这两种酶分别以7：3的比例出现在周质中。结果提示，α2Gamma2 MDH可能是在制备过程中由α2Gamma2酶产生的。(3)从甘油培养的细胞膜中纯化了ADH，并证明ADH在洗涤剂溶液中能还原泛醌-10和短侧链同系物。乙醇氧化酶呼吸链被重组为含有ADH、辅酶Q-10和细胞色素bo的蛋白脂质体。从乙酸乙酸杆菌和亚羟基葡糖杆菌中纯化的ADHS已经建立了这样的重组。亚羟基丁酸脱氢酶解离为亚基I、亚基III和亚基II，分别为奎诺血红蛋白脱氢酶部分和二血红素细胞色素c。较少

Acetobacter methanolicus is a unique acetic acid bacterium which has a methanol oxidase respiratory chain, as seen in methylotrophs, in addition to its ethanol oxidase respiratory chain. In this study, the relationship between methanol and ethanol oxidase respiratory chains was investigated. Furhtermore, in this study, the structure and function of methanol dehydrogenase (MDH) purified from A. methatiolicus and alcohol dehydrogenases (ADH) purified from several acetic acid bacteria including A. metizanolicus. (1) A. methanolicus grown on methanol exhibited a high methanol oxidase activity and contained a cytochrome c oxidase, cytochrome co, while the cells grown on glycerol showed higher ethanol oxidase activity and contained an ubiquinol oxidase, cytochrome bo. The results obtained in this study suggest that A. methanolicus has two independent respiratory chains for methanol and ethanol. The methanol oxidase respiratory chain appears to operate by linking MDH to cytochrome c oxidase, … More cytochrome co, via soluble cytochrome(s) c, while the ethanol oxidase respiratory chain consists of ADH, ubiquinone and cytochrome bo ubiquinol oxidase. (2) Two different types of MDH were purified from A. methanolicus grown on methanol. One had an alpha2gamma2structure while the other did an alpha2gamma2 structure. Both types of enzyme had been detected in the periplasm at a ratio of 7 : 3, respectively. The results obtained here suggested that the alpha2gamma2 MDH may be produced from the alpha2gamma2 enzyme during the preparation. (3) ADH was purified from the membranes of glycerol-grown cells and shown to reduce ubiquinone-10 as well as a short side-chain homologue in detergent solution. The ethanol oxidase respiratory chain was reconstituted into proteoliposomes containing ADH together with ubiquinone-10 and cytochrome bo. Such a reconstitution has been established with ADHs purified from both Acetobacter aceti and Gluconobacter suboxydans. G. suboxydans ADH was dissociated into the subunit I, III and the subunit II, which were shown to be a quinohemoprotein dehydrogenase portion and diheme cytochrome c, respectively. Less