 ISSN 0235-7216
ISSN 2424-4538 (online)
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2011 m. Nr. 3
 Studies of quinone cytotoxicity mechanisms: determination of quinone / semiquinone redox couple potential according to quinone-mediated ascorbate oxidation kinetics
Audronė MAROZIENĖ, Aušra NEMEIKAITĖ-ČĖNIENĖ, Narimantas ČĖNAS
Quinone / semiquinone redox couple potentials in aqueous media (potentials of singleelectron reduction, E17 ) are usually determined by the pulse-radiolysis technique, but also alternative methods of redox potential determination are of some interest. We have found that the rate of oxygen uptake during ascorbate oxidation by a series of quinones (n = 11) with available E17 values is characterized by a well-expressed log (rate constant) vs. E17 relationship. It enabled us to obtain previously unknown E17 values for several (n = 7) quinones with an error less than ±0.03 V. Our data enabled to demonstrate the role of acyloxy and hydroxyl substituents in the energetics of single-electron reduction of quinones and to clarify the mechanism of cytotoxicity of several quinones in bovine leukemia virus-transformed lamb kidney fibroblasts.
Keywords: quinone, reduction potential, ascorbate, cytotoxicity
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