INVOLVEMENT OF INTRA-MITOCHONDRIAL PROTONS IN REDOX REACTIONS OF CYTOCHROME-A
INVOLVEMENT OF INTRA-MITOCHONDRIAL PROTONS IN REDOX REACTIONS OF CYTOCHROME-A
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DOI：
10.1016/0014-5793(78)80327-5
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发表时间：
1978-01-01
期刊：
影响因子：
3.5
通讯作者：
SKULACHEV, VP
中科院分区：
文献类型：
--
作者：
ARTZATBANOV, VY;KONSTANTINOV, AA;SKULACHEV, VP
线粒体细胞色素氧化酶的能量保存功能被广泛认为在于电子的跨膜转移[l-4]，最初由Mitchell[5]提出。另一方面，质子参与细胞色素氧化酶反应在很大程度上被忽视了（但见[6-8]），尽管氧还原为水不仅需要4个e离子，而且需要4个H+离子。我们证实了一个重要的观察结果[9,10]，即细胞色素氧化酶高电位血红素的Em是pH依赖性的[1 I]。我们还发现线粒体内的pH值，被I？细胞色素氧化酶[111]。由于当时认为细胞色素氧化酶的高电位组分代表血红素a3[2,12 -141]，我们将我们的结果解释为血红素a3定位于线粒体膜的内表面的证据[111]。最近修订的细胞色素氧化酶光谱和电位特性[15-171]使我们重新研究这个问题。这里报道的数据（参见[181]）表明：(1)在细胞色素氧化酶的高电位氧化还原转变中，细胞色素a和a3都具有部分氧化还原连接的质子化特征。(2)已知与细胞色素发生反应的细胞色素a，缩写：E，，中点氧化还原电位；CCCP，羰基氰化甲基苯基腙；玫瑰,N-2-bydruxyetbylpiperazine-N-24hanesulfonate;拖把,morpholinopropanesulfonate;三，三羟基甲基)氨基甲烷
The energy-conserving function of mitochondrial cytochrome oxidase has been widely believed to consist in the transmembrane transfer of an electron [l-4], as originally proposed by Mitchell [5]. On the other hand, involvement of protons in the cytochrome oxidase reaction was largely neglected (but see [6-8]), although reduction of oxygen to water needs not only 4 e-but also 4 H+ ions. We confirmed the important observation [9, 10] that Em of the high-potential heme of cytochrome oxidase was pH dependent [1 I]. We also found that it was pH inside mitochondria, that was ‘felt’by I?,,, of cytochrome oxidase [111. Since the high-potential component of cytochrome oxidase was thought at that time to represent heme a3 [2, 12-141, we interpreted our results as evidence for heme a3 being localized at the inner face of the mitochondrial membrane [111. Recent revision of the cytochrome oxidase spectral and potentiometric characteristics [15-171 made us re-investigate the problem. The data reported here (see also [181) indicate that:(1) Partial redox-linked protonation is characteristic of both cytochromes a and a3 in the high-potential redox transition of cytochrome oxidase.(2) Cytochrome a, known to react with cytochromeAbbreviations: E,, midpoint redox potential; CCCP, carbony1 cyanide mchlorophenyl hydrazone; Hepes, N-2-bydruxyetbylpiperazine-N-24hanesulfonate; Mops, morpholinopropanesulfonate; Tris, tris0lydroxymethYl) aminu methane