Redox equilibration after one-electron reduction of cytochrome c oxidase: radical formation and a possible hydrogen relay mechanism
| Autor: | Damian Ashe, Peter Nicholls, Michael T. Wilson, Dimitri A. Svistunenko, Trevor Alleyne |
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| Rok vydání: | 2014 |
| Předmět: |
Cytochrome
Free Radicals Biophysics Photochemistry Biochemistry Redox Models Biological law.invention Cyclic N-Oxides Electron Transport Electron Transport Complex IV chemistry.chemical_compound Electron transfer law Cytochrome c oxidase Animals Horses Electron paramagnetic resonance Molecular Biology biology Cytochrome c peroxidase Chemistry Cytochrome c Myocardium Electron Spin Resonance Spectroscopy Cytochromes c Kinetics Heme A Spectrophotometry biology.protein Cattle Spin Labels Oxidation-Reduction Hydrogen |
| Zdroj: | Archives of biochemistry and biophysics. 554 |
| ISSN: | 1096-0384 |
| Popis: | Kinetic studies using UV/visible and EPR spectroscopy were carried out to follow the distribution of electrons within beef heart cytochrome c oxidase (CcO), both active and cyanide-inhibited, following addition of reduced cytochrome c as electron donor. In the initial one-electron reduced state the electron is shared between three redox centers, heme a, CuA and a third site, probably CuB. Using a rapid freeze system and the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) a protein radical was also detected. The EPR spectrum of the DMPO adduct of this radical was consistent with tyrosyl radical capture. This may be a feature of a charge relay mechanism involved in some part of the CcO electron transfer system from bound cytochrome c via CuA and heme a to the a3CuB binuclear center. |
| Databáze: | OpenAIRE |
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