Over the past decades, models of the organization of mitochondrial respiratory system have been controversial. The goal of this perspective is to assess this “conflict of models” by focusing on specific kinetic evidence in the two distinct segments of Coenzyme Q- and Cytochrome c-mediated electron transfer. Respiratory supercomplexes provide kinetic advantage by allowing a restricted diffusion of Coenzyme Q and Cytochrome c, and short-range interaction with their partner enzymes. In particular, electron transfer from NADH is compartmentalized by channeling of Coenzyme Q within supercomplexes, whereas succinate oxidation proceeds separately using the free Coenzyme Q pool. Previous evidence favoring Coenzyme Q random diffusion in the NADH-dependent electron transfer is due to downstream flux interference and misinterpretation of results. Indeed, electron transfer by complexes III and IV via Cytochrome c is less strictly dependent on substrate channeling in mammalian mitochondria. We briefly describe these differences and their physiological implications.

在过去的几十年里，线粒体呼吸系统的组织模型一直存在争议。这一观点的目标是通过关注辅酶 Q 和细胞色素 c 介导的电子转移两个不同部分的特定动力学证据来评估这种“模型冲突”。呼吸超复合物通过允许辅酶 Q 和细胞色素 c 的有限扩散以及与其伙伴酶的短程相互作用来提供动力学优势。特别是，来自 NADH 的电子转移通过超复合物内辅酶 Q 的通道来划分，而琥珀酸氧化则使用游离辅酶 Q 池单独进行。先前有利于辅酶 Q 在 NADH 依赖性电子转移中随机扩散的证据是由于下游通量干扰和对结果的误解。事实上，复合物 III 和 IV 通过细胞色素 c 进行的电子转移不太严格地依赖于哺乳动物线粒体中的底物通道。我们简要描述这些差异及其生理意义。