The reduction of porphyrin cytochrome c by hydrated electrons and the subsequent electron transfer reaction from reduced porphyrin cytochrome c to ferricytochrome c
| Autor: | J. De Kok, R. Braams, B.F. Van Gelder, J. Butler |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
biology
Chemistry Myocardium Cytochrome c Osmolar Concentration Electric Conductivity Biophysics Cytochrome c Group Electrons Protonation Cell Biology Photochemistry Biochemistry Porphyrin Ion Electron Transport chemistry.chemical_compound Electron transfer Reaction rate constant Ionic strength Radiolysis biology.protein Animals Horses Oxidation-Reduction |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Bioenergetics. 460:290-298 |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/0005-2728(77)90215-8 |
| Popis: | 1. 1. Hydrated electrons, produced by pulse radiolysis, react with porphyrin cytochrome c with a bimolecular rate constant of 3 · 10 10 M −1 · s −1 at 21 °C and pH 7.4. 2. 2. After the reduction step an absorbance change with a half-life of 5 μs is observed in the spectral range of 430–470 nm. A relatively stable intermediate then decays with a half-life of 15 s. 3. 3. The spectrum of the intermediate observed 50 μs after the generation of hydrated electrons shows a broad absorption band between 600 and 700 nm and a peak at 408 nm. The spectrum is attributed to the protonated form of an initially produced porphyrin anion radical. 4. 4. Reduced porphyrin cytochrome c reacts with ferricytochrome c with a bimolecular rate constant of 2 · 10 5 M −1 · s −1 in 2 mM phosphate pH 7.4, at 21 °C and of 2 · 10 6 M −1 · s −1 under the same conditions but at 1 M ionic strength. It is proposed that electron transfer in the analogous exchange reaction between ferrocytochrome c and ferricytochrome c occurs via the exposed part of the haem. |
| Databáze: | OpenAIRE |
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