CHARACTERIZATION OF REACTION BETWEEN FERROCYTOCHROME C AND CYTOCHROME-C OXIDASE
CHARACTERIZATION OF REACTION BETWEEN FERROCYTOCHROME C AND CYTOCHROME-C OXIDASE
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DOI：
10.1111/j.1432-1033.1975.tb04102.x
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发表时间：
1975-01-01
期刊：
影响因子：
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通讯作者：
ANDREASSON, LE
中科院分区：
文献类型：
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作者：
ANDREASSON, LE
用停流法研究了细胞色素氧化酶与铁细胞色素的反应。已经发现氧化酶中只有一个电子受体，即血红素基团被细胞染色快速还原。N3−的存在不影响受体的还原，这支持了这与细胞染色质相同的假设。结果与细胞染色剂和细胞染色剂之间存在简单的平衡相一致：平衡常数对应于细胞染色剂的氧化还原电位30 mV高于pH 7.4的细胞染色剂。a3+/a2+对的氧化还原电位为285 mV（基于细胞色素的255 mV电位），以及还原形式的光学性质表明，它与电位滴定中所见的还原血红素都不相同。由于细胞色素的快速还原而产生的氧化酶物种被认为代表了一个亚稳态的中间状态，在厌氧条件下，最终转化为一个更稳定的状态，其特征是高电位血红素的减少。
The reaction between cytochromecoxidase and ferrocytochromechas been investigated by the stopped‐flow method. It has been found that only one electron acceptor, a heme group, in the oxidase is rapidly reduced by cytochromec. The presence of N3−does not affect the reduction of the acceptor, which supports the hypothesis that this is identical with cytochromea. The results are consistent with the existence of a simple equilibrium between cytochromeaand cytochromec:with an equilibrium constant corresponding to an oxidation‐reduction potential of cytochromea30 mV higher than that for cytochromecat pH 7.4. The oxidation‐reduction potential of thea3+/a2+couple, 285 mV (based on a potential of 255 mV for cytochromec), and the optical properties of the reduced form indicate that it is identical with neither of the reduced hemes seen in potentiometric titrations. The oxidase species resulting from the rapid reduction of cytochromeaby cytochromecis proposed to represent a metastable intermediate state which, under anaerobic conditions, eventually is transformed into a more stable state characterized by a reduced high‐potential heme.