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>Molybdenum and vanadium nitrogenases of Azotobacter chroococcum. Low temperature favours N2 reduction by vanadium nitrogenase
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Molybdenum and vanadium nitrogenases of Azotobacter chroococcum. Low temperature favours N2 reduction by vanadium nitrogenase
pA comparison of the effect of temperature on the reduction of N2 by purified molybdenum nitrogenase and vanadium nitrogenase of Azotobacter chroococcum showed differences in behaviour. As the assay temperature was lowered from 30 degrees C to 5 degrees C N2 remained an effective substrate for V nitrogenase, but not Mo nitrogenase, since the specific activity for N2 reduction by Mo nitrogenase decreased 10-fold more than that of V nitrogenase. Activity cross-reactions between nitrogenase components showed the enhanced low-temperature activity to be associated with the Fe protein of V nitrogenase. The lower activity of homologous Mo nitrogenase components, although dependent on the ratio of MoFe protein to Fe protein, did not equal that of V nitrogenase even under conditions of high electron flux obtained at a 12-fold molar excess of Fe protein./p
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机译:比较温度对绿球藻固氮菌纯化的钼固氮酶和钒固氮酶还原N2的影响,表现出不同的行为。随着测定温度从30摄氏度降低到5摄氏度,N 2仍然是V固氮酶的有效底物,而不是Mo固氮酶,因为Mo固氮酶还原N2的比活性比V固氮酶降低了10倍。固氮酶组分之间的活性交叉反应显示增强的低温活性与V固氮酶的Fe蛋白有关。同源的Mo固氮酶组分的较低活性,尽管取决于MoFe蛋白与Fe蛋白的比例,但即使在摩尔浓度为Fe蛋白12倍的高电子通量条件下,也不等于V固氮酶。 p >
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