FEBS Letters | |
Kinetic evidence for the re‐definition of electron transfer pathways from cytochrome c to O2 within cytochrome oxidase | |
Greenwood, Colin1  Hill, Bruce C.1  | |
[1] School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, England | |
关键词: Cytochrome c oxidase; O2 reduction; Electron transfer; Flow-flash photolysis spectrophotometry; Cytochrome c; Ionic strength effect; TMPD; N; N; N′; N′-tetramethyl-p-phenylenediamine; EPR; electron paramagnetic resonance; | |
DOI : 10.1016/0014-5793(84)80113-1 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
The reaction with O2 of equimolar mixtures of cytochrome c and cytochrome c oxidase in high and low ionic strength buffers has been examined by flow-flash spectrophotometry at room temperature. In low ionic strength media where cytochrome c and the oxidase are bound in an electrostatic, 1:1 complex some of the cytochrome c is oxidised at a faster rate than a metal centre of the oxidase. In contrast, when cytochrome c and cytochrome c oxidase are predominantly dissociated at high ionic strength cytochrome c oxidation occurs only slowly (t =5 s) following the complete oxidation of the oxidase. These results demonstrate that maximal rates of electron transfer from cytochrome c to O2 occur when both substrates are present on the enzyme. The heterogeneous oxidation of cytochrome c observed in the complex implies more than one route for electron transfer within the enzyme. Possibilities for new electron transfer pathways from cytochrome c to O2 are proposed.
【 授权许可】
Unknown
【 预 览 】
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RO201912020285176ZK.pdf | 424KB | download |