The mechanism of Klebsiella pneumoniae nitrogenase action. Simulation of the dependences of H2-evolution rate on component-protein concentration and ratio and sodium dithionite concentration.
The mechanism of Klebsiella pneumoniae nitrogenase action. Simulation of the dependences of H2-evolution rate on component-protein concentration and ratio and sodium dithionite concentration.
复制标题
肺炎克雷伯菌固氮酶的作用机制。
作者：
R. Thorneley
Lowe & Thorneley [(1984) Biochem.]表1和方案2中的速率常数。[j] . 224, 877-886]模拟了肺炎克雷伯菌中分离的氮酶在不同条件下的氢气生成速率。这些速率取决于组成氮酶的MoFe蛋白和Fe蛋白的比例和浓度。模拟解释了“蛋白质滴定”和“稀释效应”曲线的形状。还原剂Na2S2O4的表观Km的概念被证明是无效的，因为h2 -进化速率与S2O4（2-）浓度的平方根的关系不是双曲的，而是取决于MoFe蛋白和Fe蛋白的比例和绝对浓度。
The rate constants from Table 1 and Scheme 2 of Lowe & Thorneley [(1984) Biochem. J. 224, 877-886] were used to simulate the rate of H2 evolution, under various conditions, from nitrogenase isolated from Klebsiella pneumoniae. These rates depend on both the ratio and concentrations of the MoFe protein and Fe protein that comprise nitrogenase. The simulations explain the shapes of 'protein titration' and 'dilution effect' curves. The concept of an apparent Km for the reductant Na2S2O4 is shown to be invalid, since the dependence of H2-evolution rate on the square root of S2O4(2-) concentration is not hyperbolic and depends on the ratio and absolute concentrations of the MoFe protein and Fe protein.