颗粒性甲烷单加氧酶的研究

从甲基弯菌(Methylosinus trichosporium)IMV3011(简称M3011)的膜中分离纯化出颗粒性甲烷单加氧酶(Particulate Methane monooxygenase,简称pMMO)和NADH脱氢酶。Cu2+、不同外源电子给体、EDTA等对pMMO活性的都有影响；测定了pMMO分子量，以及其活性中心金属离子含量。对于M3011，培养基中Cu2+浓度对pMMO的生成和活性没有影响；但在分离纯化过程中对pMMO稳定性有明显影响。电镜结果显示，Cu2+浓度对pMMO的数量有较明显的影响。对于纯化的pMMO，对苯二酚仍是有效的电子供体，而NADH却是无效的电子供体。纯化过程中采用对苯二酚作为pMMO活性分析时的电子供体，排除了共纯化NADH脱氢酶的必要，有利于对pMMO活性中心进行深入研究。

Study of Particulate Methane Monooxygenase From M.3011

Particulate Monooxygenase (pMMO) and NADH-dehydrogenase were purified from membranes of Methylosinus trichosporium IMV 3011. Factors such as Cu 2+, different exogenous electron donors, ethylene diamine tetraacetic acid(EDTA) had effects on the activity of pMMO. Molecular weight of pMMO was determined by HPLC, and content of metal ion from the active center by atomic absorption spectrum analysis. The concentration of Cu 2+ had no effect on the production and activity of pMMO in the bacterial culture, but influenced the stability greatly during the purification of pMMO. Transmission electron microscope (TEM)photos of M. 3011 with different copper concentration showed that the concentration of copper decided the quantity of pMMO. Quinol was an effective exogenous electron donor for the purfied pMMO, whereas NADH aws ineffective, which meant NADH-dehydrogenase was unnecessary to be co-purified. It facilitated further study on the catalytic core of pMMO.