细胞色素c氧化酶中氧中间体之间的氧化还原转变。
Redox transitions between oxygen intermediates in cytochrome-c oxidase.
作者信息
Verkhovsky M I, Morgan J E, Wikström M
机构信息
Department of Medical Chemistry, University of Helsinki, Finland.
出版信息
Proc Natl Acad Sci U S A. 1996 Oct 29;93(22):12235-9. doi: 10.1073/pnas.93.22.12235.
Some intermediates in the reduction of O2 to water by cytochrome-c oxidase have been characterized by optical, Raman, and magnetic circular dichroism spectroscopy. The so-called "peroxy" (P) and "ferryl" (F) forms of the enzyme, which have been considered to be intermediates of the oxygen reaction, can be generated when the oxidized enzyme reacts with H2O2, or when the two-electron reduced ("CO mixed-valence") enzyme reacts with O2. The structures as well as the overall redox states of P and F have recently been controversial. We show here, using tris(2,2'-bipyridyl)ruthenium(II) as a photoinducible reductant, that one-electron reduction of P yields F, and that one-electron reduction of F yields the oxidized enzyme. This confirms that the overall redox states of P and F differ from the oxidized enzyme by two and one electron equivalents, respectively. The structures of the P and F states are discussed.
细胞色素c氧化酶将O₂还原为水的过程中的一些中间体已通过光学、拉曼和磁圆二色光谱进行了表征。该酶的所谓“过氧”（P）和“高铁”（F）形式，被认为是氧反应的中间体，当氧化型酶与H₂O₂反应时，或者当双电子还原的（“CO混合价态”）酶与O₂反应时可以生成。最近，P和F的结构以及整体氧化还原状态一直存在争议。我们在此表明，使用三（2,2'-联吡啶）钌（II）作为光诱导还原剂，P的单电子还原产生F，而F的单电子还原产生氧化型酶。这证实了P和F的整体氧化还原状态分别与氧化型酶相差两个和一个电子当量。讨论了P和F状态的结构。
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