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dc.contributor.authorButler, John
dc.contributor.authorHoey, Brigid M
dc.date.accessioned2010-08-02T16:14:58Z
dc.date.available2010-08-02T16:14:58Z
dc.date.issued1992
dc.identifier.citationReactions of glutathione and glutathione radicals with benzoquinones. 1992, 12 (5):337-45 Free Radic. Biol. Med.en
dc.identifier.issn0891-5849
dc.identifier.pmid1592273
dc.identifier.doi10.1016/0891-5849(92)90082-R
dc.identifier.urihttp://hdl.handle.net/10541/108842
dc.description.abstractThe reactions of glutathione (GSH) and glutathione radicals with a series of methyl-substituted 1,4-benzoquinones and 1,4-benzoquinone have been studied. It was found that by mixing excess benzoquinone with glutathione at pH above 6.5, the products formed were complex and unstable. All of the other experiments were carried out at pH 6.0, where the main product was stable for several hours. Stopped-flow analysis allowed the measurement of the rates of the rapid reactions between GSH and the quinones, and the products were monitored by High Performance Liquid Chromatography (HPLC). The rates of the reactions vary by five orders of magnitude and must be influenced by steric factors as well as changes in the redox states. It was observed that simple hydroquinones were not formed when the different benzoquinones were mixed with excess GSH and suggests that the initial reaction is addition/reduction rather than electron transfer. In the presence of excess quinone, the hydroquinone of the glutathione conjugate is oxidized back to its quinone. The rates of the reaction were measured. By using the technique of pulse radiolysis, it was possible to measure the reduction of the quinones by GSSG.- and the oxidation of hydroquinones by GS(.). It is proposed that the appearance of GSSG in reactions of quinones with glutathione could be due to oxidation of the hydroquinone by oxygen and the subsequent superoxide or H2O2 promoting the oxidation of GSH to GSSG.
dc.language.isoenen
dc.subject.meshBenzoquinones
dc.subject.meshChromatography, High Pressure Liquid
dc.subject.meshFree Radicals
dc.subject.meshGlutathione
dc.subject.meshHydrogen-Ion Concentration
dc.subject.meshHydroquinones
dc.subject.meshOxidation-Reduction
dc.subject.meshSpectrophotometry
dc.titleReactions of glutathione and glutathione radicals with benzoquinones.en
dc.typeArticleen
dc.contributor.departmentCRC Department of Biophysical Chemistry, Paterson Institute for Cancer Research, Christie Hospital and Holt Radium Institute, Manchester, England.en
dc.identifier.journalFree Radical Biology & Medicineen
html.description.abstractThe reactions of glutathione (GSH) and glutathione radicals with a series of methyl-substituted 1,4-benzoquinones and 1,4-benzoquinone have been studied. It was found that by mixing excess benzoquinone with glutathione at pH above 6.5, the products formed were complex and unstable. All of the other experiments were carried out at pH 6.0, where the main product was stable for several hours. Stopped-flow analysis allowed the measurement of the rates of the rapid reactions between GSH and the quinones, and the products were monitored by High Performance Liquid Chromatography (HPLC). The rates of the reactions vary by five orders of magnitude and must be influenced by steric factors as well as changes in the redox states. It was observed that simple hydroquinones were not formed when the different benzoquinones were mixed with excess GSH and suggests that the initial reaction is addition/reduction rather than electron transfer. In the presence of excess quinone, the hydroquinone of the glutathione conjugate is oxidized back to its quinone. The rates of the reaction were measured. By using the technique of pulse radiolysis, it was possible to measure the reduction of the quinones by GSSG.- and the oxidation of hydroquinones by GS(.). It is proposed that the appearance of GSSG in reactions of quinones with glutathione could be due to oxidation of the hydroquinone by oxygen and the subsequent superoxide or H2O2 promoting the oxidation of GSH to GSSG.


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