Role of Superoxide Anions in the Redox Changes Affecting the Physiologically Occurring Cu(I)-Glutathione Complex

The physiologically occurring copper-glutathione complex, [Cu(I)-[GSH]2], has the ability to react continually with oxygen, generating superoxide anions (O2•−). We addressed here the effects that superoxide removal has on the redox state of Cu(I) and GSH present in such complex and assessed the form...

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Main Authors: Hernán Speisky, Camilo López-Alarcón, Claudio Olea-Azar, Cristian Sandoval-Acuña, Margarita E. Aliaga
Format: Article
Language:English
Published: Wiley 2011-01-01
Series:Bioinorganic Chemistry and Applications
Online Access:http://dx.doi.org/10.1155/2011/674149
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author Hernán Speisky
Camilo López-Alarcón
Claudio Olea-Azar
Cristian Sandoval-Acuña
Margarita E. Aliaga
author_facet Hernán Speisky
Camilo López-Alarcón
Claudio Olea-Azar
Cristian Sandoval-Acuña
Margarita E. Aliaga
author_sort Hernán Speisky
collection DOAJ
description The physiologically occurring copper-glutathione complex, [Cu(I)-[GSH]2], has the ability to react continually with oxygen, generating superoxide anions (O2•−). We addressed here the effects that superoxide removal has on the redox state of Cu(I) and GSH present in such complex and assessed the formation of Cu(II)-GSSG as a final oxidation product. In addition, we investigated the potential of a source of O2•− external to the Cu(I)-[GSH]2 complex to prevent its oxidation. Removal of O2•− from a Cu(I)-[GSH]2-containing solution, whether spontaneous or Tempol-induced, led to time-dependent losses in GSH that were greater than those affecting the metal. The losses in GSH were not accompanied by increments in GSSG but were largely accounted for by the cumulative formation of Cu(II)-GSSG molecules. Notably, the redox changes in Cu(I) and GSH were totally prevented when Cu(I)-[GSH]2 was coincubated with hypoxanthine/xanthine oxidase. Data suggest that the generation of O2•− by Cu(I)-[GSH]2 implies the obliged formation of an intermediate whose subsequent oxidation into Cu(II)-GSSG or back reduction into Cu(I)-[GSH]2 is favoured by either the removal or the addition of O2•−, respectively.
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spelling doaj-art-451a1b9a6a35450c86f2a5ec7a3e45a62025-08-20T02:37:47ZengWileyBioinorganic Chemistry and Applications1565-36331687-479X2011-01-01201110.1155/2011/674149674149Role of Superoxide Anions in the Redox Changes Affecting the Physiologically Occurring Cu(I)-Glutathione ComplexHernán Speisky0Camilo López-Alarcón1Claudio Olea-Azar2Cristian Sandoval-Acuña3Margarita E. Aliaga4Nutrition and Food Technology Institute, University of Chile, Santiago 7830489, ChileFacultad de Química, Pontificia Universidad Católica de Chile, Santiago 6094411, ChileFaculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago 8380492, ChileNutrition and Food Technology Institute, University of Chile, Santiago 7830489, ChileFacultad de Química, Pontificia Universidad Católica de Chile, Santiago 6094411, ChileThe physiologically occurring copper-glutathione complex, [Cu(I)-[GSH]2], has the ability to react continually with oxygen, generating superoxide anions (O2•−). We addressed here the effects that superoxide removal has on the redox state of Cu(I) and GSH present in such complex and assessed the formation of Cu(II)-GSSG as a final oxidation product. In addition, we investigated the potential of a source of O2•− external to the Cu(I)-[GSH]2 complex to prevent its oxidation. Removal of O2•− from a Cu(I)-[GSH]2-containing solution, whether spontaneous or Tempol-induced, led to time-dependent losses in GSH that were greater than those affecting the metal. The losses in GSH were not accompanied by increments in GSSG but were largely accounted for by the cumulative formation of Cu(II)-GSSG molecules. Notably, the redox changes in Cu(I) and GSH were totally prevented when Cu(I)-[GSH]2 was coincubated with hypoxanthine/xanthine oxidase. Data suggest that the generation of O2•− by Cu(I)-[GSH]2 implies the obliged formation of an intermediate whose subsequent oxidation into Cu(II)-GSSG or back reduction into Cu(I)-[GSH]2 is favoured by either the removal or the addition of O2•−, respectively.http://dx.doi.org/10.1155/2011/674149
spellingShingle Hernán Speisky
Camilo López-Alarcón
Claudio Olea-Azar
Cristian Sandoval-Acuña
Margarita E. Aliaga
Role of Superoxide Anions in the Redox Changes Affecting the Physiologically Occurring Cu(I)-Glutathione Complex
Bioinorganic Chemistry and Applications
title Role of Superoxide Anions in the Redox Changes Affecting the Physiologically Occurring Cu(I)-Glutathione Complex
title_full Role of Superoxide Anions in the Redox Changes Affecting the Physiologically Occurring Cu(I)-Glutathione Complex
title_fullStr Role of Superoxide Anions in the Redox Changes Affecting the Physiologically Occurring Cu(I)-Glutathione Complex
title_full_unstemmed Role of Superoxide Anions in the Redox Changes Affecting the Physiologically Occurring Cu(I)-Glutathione Complex
title_short Role of Superoxide Anions in the Redox Changes Affecting the Physiologically Occurring Cu(I)-Glutathione Complex
title_sort role of superoxide anions in the redox changes affecting the physiologically occurring cu i glutathione complex
url http://dx.doi.org/10.1155/2011/674149
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