己糖激酶催化反应的热力学。II. 作为镁离子浓度函数的反应焓的测量与计算。

Thermodynamics of hexokinase catalyzed reactions. II. Measurement and calculation of enthalpies of reaction as a function of magnesium ion concentration.

作者信息

Goldberg R N

出版信息

Biophys Chem. 1976 May;4(3):215-21. doi: 10.1016/0301-4622(76)80067-1.

Abstract

Enthalpies of phosphorylation of glucose by adenosine 5'-triphosphate have been measured as a function of concentrations of magnesium chloride in TRIS/TRIS-HCl buffer in the pH range 8.64 to 8.98. These measurements are compared with the results of calculations of these enthalpies that use a coupled equilibrium formalism with equilibrium data and enthalpy values selected from the literature. The experimental results span the range of magnesium ion concentrations 1 X 10(-6) to 0.3 mol alpha-1 and show a total variation in the enthalpy of reaction of almost 10 kJ mol-1, with the most exothermic reaction occurring at a magnesium ion concentration of 6.0 X 10(-4) mol alpha-1. The calculated enthalpies of reaction, except for the magnesium ion concentration range 4 X 10(-6) to 5 X 10(-4) mol alpha-1, are, within estimated uncertainty intervals (0.8 to 10.2 kJ mol-1), in agreement with the measured values.

摘要

在pH值范围为8.64至8.98的TRIS/TRIS - HCl缓冲液中，已测量了三磷酸腺苷（ATP）对葡萄糖磷酸化的焓变与氯化镁浓度的函数关系。将这些测量结果与使用耦合平衡形式并结合从文献中选取的平衡数据和焓值对这些焓变进行计算的结果进行了比较。实验结果涵盖了镁离子浓度从1×10⁻⁶到0.3 mol·L⁻¹的范围，反应焓的总变化几乎为10 kJ·mol⁻¹，最放热的反应发生在镁离子浓度为6.0×10⁻⁴ mol·L⁻¹时。除了镁离子浓度范围为4×10⁻⁶至5×10⁻⁴ mol·L⁻¹外，计算得到的反应焓在估计的不确定区间（0.8至10.2 kJ·mol⁻¹）内与测量值一致。