Single catalytic site model for the oxidation of ferrocytochrome c by mitochondrial cytochrome c oxidase.
Single catalytic site model for the oxidation of ferrocytochrome c by mitochondrial cytochrome c oxidase.
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DOI：
10.1073/pnas.81.2.347
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发表时间：
1984
影响因子：
11.1
通讯作者：
S. Speck;D. Dye;E. Margoliash
中科院分区：
文献类型：
--
作者：
S. Speck;D. Dye;E. Margoliash
提出了一个单一的催化位点模型来解释由细胞色素c氧化酶（ferrocytochrome c：氧氧化还原酶，EC 1.9.3.1）氧化亚铁细胞色素c的多相动力学。该模型涉及非生产性结合的底物的催化位点附近的细胞色素c氧化酶的细胞色素c，降低细胞色素c的结合常数在催化位点。这种底物抑制导致铁细胞色素c-细胞色素c氧化酶复合物解离的一阶速率常数增加，这是在分光光度测定中细胞色素c和细胞色素c氧化酶之间电子的稳态周转中的限速步骤，产生初始速率以及米氏常数的增加-即多个动力学阶段。
A single catalytic site model is proposed to account for the multiphasic kinetics of oxidation of ferrocytochrome c by cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1). This model involves nonproductive binding of substrate to sites near the catalytic site on cytochrome c oxidase for cytochrome c, decreasing the binding constant for cytochrome c at the catalytic site. This substrate inhibition results in an increase in the first-order rate constant for the dissociation of the ferricytochrome c-cytochrome c oxidase complex, the rate-limiting step in the steady-state turnover of electrons between cytochrome c and cytochrome c oxidase in the spectrophotometric assay, yielding increases in the initial rate as well as the Michaelis constant--namely, multiple kinetic phases.