The Autoxidation of the Reduced Forms of EO9
| Autor: | V J Spanswick, John Butler, Jeffrey Cummings |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Indoles
Free Radicals Semiquinone Aziridines chemistry.chemical_element Antineoplastic Agents Photochemistry Biochemistry Oxygen chemistry.chemical_compound Drug Stability Indolequinones Xanthine oxidase Autoxidation Hydroquinone Cytochrome P450 reductase General Medicine Hydrogen-Ion Concentration Hydroquinones Quinone chemistry Spectrophotometry One-electron reduction Pulse Radiolysis Oxidation-Reduction Half-Life |
| Zdroj: | Free Radical Research. 25:141-148 |
| ISSN: | 1029-2470 1071-5762 |
| DOI: | 10.3109/10715769609149919 |
| Popis: | The properties of the semiquinone radical from [3-hydroxy-5-aziridinyl-1-methyl-2-(1H-indole-4,7-indi one)-prop-beta-en-alpha-ol], EO9, have been studied using pulse-radiolysis techniques. The reduction potential of the semiquinone of EO9 at pH7.4, E(EO9/EO9-), is -253 +/- 6 mV and hence this quinone can be readily reduced by one-electron reducing enzymes such as cytochrome P450 reductase and xanthine oxidase. However, the radical is unstable in the presence of oxygen (k = 1.3 +/- 0.15 x 10(8) M-1 s-1). The semiquinone radicals and the hydroquinone are in equilibrium although the formation of the hydroquinone is favoured t physiologically relevant pH. The hydroquinone of EO9 is also unstable in the presence of oxygen and it is predicted that in fully aerated solutions, its half life is 1.5 +/- 0.3 seconds. These results are discussed in view of the selective cytotoxicity of EO9 and its ability to undergo bioreductive activation by one-electron reducing enzymes and DT-diaphorase. |
| Databáze: | OpenAIRE |
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