Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary.
Int J Biochem Cell Biol. 2019 Oct;115:105580. doi: 10.1016/j.biocel.2019.105580. Epub 2019 Aug 5.
During tissue ischemia succinate accumulates. Herein, literature spanning the past nine decades is reviewed leaning towards the far greater role of Krebs cycle's canonical activity yielding succinate through α-ketoglutarate -> succinyl-CoA -> succinate even in hypoxia, as opposed to reversal of succinate dehydrogenase. Furthermore, the concepts of i) a diode-like property of succinate dehydrogenase rendering it difficult to reverse, and ii) the absence of mammalian mitochondrial quinones exhibiting redox potentials in the [-60, -80] mV range needed for fumarate reduction, are discussed. Finally, it is emphasized that a "fumarate reductase" enzyme entity reducing fumarate to succinate found in some bacteria and lower eukaryotes remains to be discovered in mammalian mitochondria.
在组织缺血期间，琥珀酸积累。本文综述了过去九十年的文献，倾向于认为克雷布斯循环的经典活性通过α-酮戊二酸->琥珀酰辅酶 A->琥珀酸产生琥珀酸的作用要大得多，即使在缺氧情况下也是如此，而不是琥珀酸脱氢酶的逆转。此外，还讨论了琥珀酸脱氢酶的 i）二极管样特性使其难以逆转，以及 ii）哺乳动物线粒体醌不存在还原电位在[-60，-80] mV 范围内，这是需要琥珀酸还原的条件，的概念。最后，强调了在哺乳动物线粒体中仍然需要发现某些细菌和低等真核生物中发现的将延胡索酸还原为琥珀酸的“延胡索酸还原酶”酶实体。
