OXYGEN-BINDING AND ACTIVATION - EARLY STEPS IN THE REACTION OF OXYGEN WITH CYTOCHROME-C-OXIDASE
OXYGEN-BINDING AND ACTIVATION - EARLY STEPS IN THE REACTION OF OXYGEN WITH CYTOCHROME-C-OXIDASE
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DOI：
10.1021/bi00176a042
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发表时间：
1994-03-15
期刊：
影响因子：
2.9
通讯作者：
WIKSTROM, M
中科院分区：
文献类型：
--
作者：
VERKHOVSKY, MI;MORGAN, JE;WIKSTROM, M
我们已经研究了充分还原的细胞色素c氧化酶与高浓度的氧（1 mM）的流动闪光反应，记录在400和455 nm之间的一些波长的反应的第一个200 μ s。这种方法使我们能够观察到动力学阶段的时间常数为8和32 μ s，并将它们的光谱分开。第一阶段的光谱与氧结合肌红蛋白的光谱相当，而第二阶段的光谱似乎包含来自过氧中间体的贡献。结果进行了讨论的背景下，在一个模型中，其中的8亩相反映了氧结合态的平衡的建立，而32亩相出现时，该系统被困作为一个过氧中间体，通过血红素间电子转移。
We have studied the flow-flash reaction of fully reduced cytochrome c oxidase with a high concentration of oxygen (1 mM), recording the first 200 mu s of the reaction at a number of wavelengths between 400 and 455 nm. This approach has allowed us to observe kinetic phases with time constants of 8 and 32 mu s and to separate their spectra. The spectrum of the first phase is comparable to that of oxygen binding to myoglobin, while the spectrum of the second phase appears to contain a contribution from a peroxy intermediate. The results are discussed in the context of a model in which the 8-mu s phase reflects the establishment of an equilibrium of oxygen-bound states, while the 32-mu s phase arises when this system is trapped as a peroxy intermediate, by inter-heme electron transfer.