The aim of the study was to evaluate the interplay between mitochondrial respiration and H2O2 release during the transition from basal non-phosphorylating to maximal phosphorylating states. We conducted a large scale comparative study of mitochondrial oxygen consumption, H2O2 release and electron leak (% H2O2/O) in skeletal muscle mitochondria isolated from mammal species ranging from 7 g to 500 kg. Mitochondrial fluxes were measured at different steady state rates in presence of pyruvate, malate, and succinate as respiratory substrates. Every species exhibited a burst of H2O2 release from skeletal muscle mitochondria at a low rate of oxidative phosphorylation, essentially once the activity of mitochondrial oxidative phosphorylation reached 26% of the maximal respiration. This threshold for ROS generation thus appears as a general characteristic of skeletal muscle mitochondria in mammals. These findings may have implications in situations promoting succinate accumulation within mitochondria, such as ischemia or hypoxia.

中文翻译：

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哺乳动物骨骼肌中 H2O2 释放的线粒体阈值

该研究的目的是评估从基础非磷酸化状态过渡到最大磷酸化状态期间线粒体呼吸和 H2O2 释放之间的相互作用。我们对从 7 g 到 500 kg 的哺乳动物物种中分离的骨骼肌线粒体中的线粒体耗氧量、H2O2 释放和电子泄漏 (% H2O2/O) 进行了大规模比较研究。在丙酮酸、苹果酸和琥珀酸作为呼吸底物存在的情况下，以不同的稳态速率测量线粒体通量。每个物种都以低氧化磷酸化速率从骨骼肌线粒体中释放出大量 H2O2，基本上是在线粒体氧化磷酸化活性达到最大呼吸的 26% 时。因此，ROS 生成的这一阈值表现为哺乳动物骨骼肌线粒体的一般特征。这些发现可能对促进线粒体内琥珀酸积累的情况有影响，例如缺血或缺氧。