颗粒性甲烷单加氧酶的电子供体研究

Study on the Electron Donors for Particulate Monooxygenase

从甲基弯菌 Methylosinus trichosporium IMV 30 11的膜中分离出颗粒性甲烷单加氧酶 (Particulate MMO,p MMO)和 NADH脱氢酶 .只有当两者同时存在、并添加去垢剂解离膜组分时 ,NADH才能为 p MMO提供还原当量 .对苯二酚能够在整细胞和膜水平代替 NADH作为 p MMO的电子供体 .对于纯化的 p MMO,对苯二酚仍是有效的电子供体 ,而 NADH却是无效的电子供体 .在 NADH脱氢酶存在下 ,NADH可将对苯醌还原为对苯二酚 .纯化过程中 ,采用对苯二酚作为 p MMO活性分析时的电子供体 ,不必共纯化 NADH脱氢酶 ,且有利于对p

Particulate Monooxygenase (pMMO) and NADH-dehydrogenase were purified from membranes of the methane-oxidizing bacterium Methylosinus trichosporium IMV 3011. NADH can provide reducing equivalents for pMMO only in the presence of these two enzymes and the membrane fraction solubilized by the detergent. Quinol is an effective exogenous electron donor for pMMO, substituting for NADH in whole cells and membranes. Furthermore, quinol is an effective exogenous electron donor also for the purified pMMO, whereas NADH is ineffective. Quinone can be reduced to quinol by NADH in the presence of NADH-dehydrogenase. The use of quinol to assay pMMO activity during purification could eliminate the need to copurify the additional NADH-dehydrogenase and facilitate the further study on the catalytic core of pMMO.