Stucki J W
Pharmakologisches Institut der Universität Bern, Switzerland.
Proc Biol Sci. 1991 Jun 22;244(1311):197-202. doi: 10.1098/rspb.1991.0070.
A new method was developed to analyse the dynamic properties of oxidative phosphorylation, in particular the sensitivity of the phosphate potential with respect to fluctuating cellular ATP utilization. This treatment is based on the eigenvalue sensitivity analysis of an experimentally supported non-equilibrium thermodynamic model of oxidative phosphorylation. Such an analysis allows direct access to the kinetic information, while circumventing the awkward conventional numerical integration of a set of nonlinear differential equations. This procedure revealed, for the parameters characteristic for liver of starved rats in vivo, that the sensitivity of oxidative phosphorylation to a fluctuating ATP utilization is minimal at a degree of coupling q = 0.95. This means that the phosphate potential is highly buffered with respect to fluctuating energy demands at the degree of coupling. This value of q agrees well with the degree of coupling qeef, at which net ATP production of oxidative phosphorylation--at optimal efficiency--occurs in the most economic way. This simultaneous maximization of kinetic stability and economic thermodynamic efficiency at the same degree of coupling appears to be a coincidence.
一种新的方法被开发出来用于分析氧化磷酸化的动态特性，特别是磷酸势对细胞内ATP利用波动的敏感性。这种处理方法基于一个经实验支持的氧化磷酸化非平衡热力学模型的特征值敏感性分析。这样的分析允许直接获取动力学信息，同时规避了一组非线性微分方程的繁琐传统数值积分。对于体内饥饿大鼠肝脏的特征参数，该程序表明，在耦合度q = 0.95时，氧化磷酸化对波动的ATP利用的敏感性最小。这意味着在该耦合度下，磷酸势相对于波动的能量需求具有高度缓冲作用。这个q值与耦合度qeef非常吻合，在该耦合度下，氧化磷酸化的净ATP产生以最经济的方式在最佳效率下发生。在相同耦合度下动力学稳定性和经济热力学效率的同时最大化似乎是一种巧合。
