Regulation of mitochondrial metabolism by the phosphorylation system and the complex IV and its impact on oxidative stress

心脏和骨骼肌收缩所需的大部分能量来自氧化磷酸化（OXPHOS），这是一个发生在线粒体内膜中的过程。OXPHOS将电子传递系统（ETS）中的电子转移与质子在膜间空间中的移动相耦合。形成的质子梯度在两个线粒体膜之间积累，并被磷酸化系统利用以ATP的形式产生能量。所产生的能量不仅取决于ETS的复合物I至IV之间的电子传递效率，还取决于磷酸化系统将质子梯度转化为能量的能力。例如，先前的研究表明，磷酸化系统对人类心脏和骨骼肌中的OXPHOS具有很强的控制作用，而这种特殊的特征并不与常用的动物模型（如小鼠和大鼠）共享。

A large fraction of energy needed for heart and skeletal muscle contraction comes from oxidative phosphorylation (OXPHOS), a process that takes place in the inner mitochondrial membrane. OXPHOS couple the transfer of electrons in the electron transport system (ETS) to the movement of protons in the intermembrane space. The proton gradient formed is accumulated between the two mitochondrial membranes and is utilized by the phosphorylation system to produce energy in the form of ATP. The energy produced depends not only from the efficiency of electron transport between the complexes I to IV of the ETS but also of the ability of the phosphorylation system to convert the proton gradient into energy. For instance, previous studies showed that the phosphorylation system exert a strong control on OXPHOS in the human heart and skeletal muscle, whereas this particular characteristic is not shared with commonly used animal models such as mice and rats.