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dc.contributor.authorKalyanaraman, B
dc.contributor.authorKorytowski, W
dc.contributor.authorPilas, B
dc.contributor.authorSarna, T
dc.contributor.authorLand, Edward J
dc.contributor.authorTruscott, T G
dc.date.accessioned2010-11-10T11:15:01Z
dc.date.available2010-11-10T11:15:01Z
dc.date.issued1988-10
dc.identifier.citationReaction between ortho-semiquinones and oxygen: pulse radiolysis, electron spin resonance, and oxygen uptake studies. 1988, 266 (1):277-84 Arch Biochem Biophysen
dc.identifier.issn0003-9861
dc.identifier.pmid2845864
dc.identifier.urihttp://hdl.handle.net/10541/115237
dc.description.abstractThe cytotoxicity to tumor cells or cardiotoxic side effects of certain para-quinone antitumor drugs have been attributed to the corresponding semiquinones and derived superoxide and hydroxyl radicals. It has also been suggested that ortho-semiquinones, including those that arise during melanogenesis, produced via either the one-electron oxidation of catechol(amine)s or the one-electron reduction of the corresponding quinones, react with molecular oxygen to give superoxide and hydrogen peroxide. Furthermore it has been shown that catechol(amine)s which form noncyclizable quinones are more cytotoxic toward melanogenic cells than those forming cyclizable quinones. In order to provide further kinetic information on the interaction of oxygen with ortho-semiquinones, using pulse radiolysis we directly measured the rates of reaction of various ortho-semiquinones with molecular oxygen. The semiquinones of the corresponding catechol(amine)s were also produced by the horseradish peroxidase/hydrogen peroxide system, and detected by electron spin resonance spectroscopy using the spin stabilization method. Oxygen consumption was monitored using a standard Clark oxygen electrode. Our data indicate that while ortho-semiquinones from catechol(amine)s and catechol estrogens do not react with molecular oxygen at a rate equal to or greater than k less than or equal to 10(5) M-1 s-1, semiquinones from hydroxy-substituted catechol(amine)s react with dioxygen with rates in the range k = 10(6)-10(7) M-1 s-1.
dc.language.isoenen
dc.subjectAnticancerous Agentsen
dc.subject.meshAntineoplastic Agents
dc.subject.meshCatecholamines
dc.subject.meshCatechols
dc.subject.meshChemical Phenomena
dc.subject.meshChemistry
dc.subject.meshElectron Spin Resonance Spectroscopy
dc.subject.meshEstrogens, Catechol
dc.subject.meshFree Radicals
dc.subject.meshOxidation-Reduction
dc.subject.meshOxygen
dc.subject.meshOxygen Consumption
dc.subject.meshQuinones
dc.titleReaction between ortho-semiquinones and oxygen: pulse radiolysis, electron spin resonance, and oxygen uptake studies.en
dc.typeArticleen
dc.contributor.departmentDepartment of Radiology, Medical College of Wisconsin, Milwaukee 53226.en
dc.identifier.journalArchives of Biochemistry and Biophysicsen
dc.identifier.pmcid10.1016/0003-9861(88)90259-7
html.description.abstractThe cytotoxicity to tumor cells or cardiotoxic side effects of certain para-quinone antitumor drugs have been attributed to the corresponding semiquinones and derived superoxide and hydroxyl radicals. It has also been suggested that ortho-semiquinones, including those that arise during melanogenesis, produced via either the one-electron oxidation of catechol(amine)s or the one-electron reduction of the corresponding quinones, react with molecular oxygen to give superoxide and hydrogen peroxide. Furthermore it has been shown that catechol(amine)s which form noncyclizable quinones are more cytotoxic toward melanogenic cells than those forming cyclizable quinones. In order to provide further kinetic information on the interaction of oxygen with ortho-semiquinones, using pulse radiolysis we directly measured the rates of reaction of various ortho-semiquinones with molecular oxygen. The semiquinones of the corresponding catechol(amine)s were also produced by the horseradish peroxidase/hydrogen peroxide system, and detected by electron spin resonance spectroscopy using the spin stabilization method. Oxygen consumption was monitored using a standard Clark oxygen electrode. Our data indicate that while ortho-semiquinones from catechol(amine)s and catechol estrogens do not react with molecular oxygen at a rate equal to or greater than k less than or equal to 10(5) M-1 s-1, semiquinones from hydroxy-substituted catechol(amine)s react with dioxygen with rates in the range k = 10(6)-10(7) M-1 s-1.


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