Control Over the Contribution of the Mitochondrial Membrane Potential (Δψ) and Proton Gradient (ΔpH) to the Protonmotive Force (Δp) IN SILICO STUDIES
Control Over the Contribution of the Mitochondrial Membrane Potential (Δψ) and Proton Gradient (ΔpH) to the Protonmotive Force (Δp) IN SILICO STUDIES
复制标题
DOI：
10.1074/jbc.m802404200
复制
发表时间：
2008-11-28
影响因子：
4.8
通讯作者：
Korzeniewski, Bernard
中科院分区：
文献类型：
--
作者：
Dzbek, Jaroslaw;Korzeniewski, Bernard
跨线粒体内膜的质子动力（Delta p）具有两个分量：膜电位（Delta Psi）和质子浓度梯度（Delta pH）。先前由Korzeniewski等人（Korzeniewski，B.，Noma，A.，和Matsuoka，S.（2005）Biophys. 116，145-157）通过包括K+单端口、跨线粒体内膜的K+/H+交换和膜电容来进行修改，以用机械确定的可变Δ Psi/Δ pH比代替先前使用的固定Δ Psi/Δ pH比。扩展模型与实验结果吻合良好。计算机模拟表明，Δ Psi和Δ pH对Δ p的贡献是由K+单端口和K+/H+交换速率常数的比值决定的，而不是由这些常数的绝对值决定的。Δ p的值主要由ATP使用量控制。对Δ Psi/Δ pH比率的代谢控制主要通过在这些过程存在下的K+单端口和K+/H+交换以及在不存在这些过程的情况下的ATP使用、ATP/ADP载体和磷酸盐载体来实现。线粒体内膜的K+循环主要由K+单通道和K+/H+交换控制，而H+循环则由ATP利用控制。它表明，二次K+离子运输是没有必要的维持生理Δ Psi/Δ pH值比。
The protonmotive force across the inner mitochondrial membrane (Delta p) has two components: membrane potential (Delta Psi) and the gradient of proton concentration (Delta pH). The computer model of oxidative phosphorylation developed previously by Korzeniewski et al. (Korzeniewski, B., Noma, A., and Matsuoka, S. (2005) Biophys. Chem. 116, 145-157) was modified by including the K+ uniport, K+/H+ exchange across the inner mitochondrial membrane, and membrane capacitance to replace the fixed Delta Psi/Delta pH ratio used previously with a variable one determined mechanistically. The extended model gave good agreement with experimental results. Computer simulations showed that the contribution of Delta Psi and Delta pH to Delta p is determined by the ratio of the rate constants of the K+ uniport and K+/H+ exchange and not by the absolute values of these constants. The value of Delta p is mostly controlled by ATP usage. The metabolic control over the Delta Psi/Delta pH ratio is exerted mostly by K+ uniport and K+/H+ exchange in the presence of these processes, and by the ATP usage, ATP/ADP carrier, and phosphate carrier in the absence of them. The K+ circulation across the inner mitochondrial membrane is controlled mainly by K+ uniport and K+/H+ exchange, whereas H+ circulation by ATP usage. It is demonstrated that the secondary K+ ion transport is not necessary for maintaining the physiological Delta Psi/Delta pH ratio.