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Selenium independent glutathione peroxidase activity associated with cationic forms of glutathione transferase in human heart

Authors :
Carmine Di Ilio
Federici G
Paolo Sacchetta
Anna Maria Caccuri
Mario Lo Bello
Source :
Journal of Molecular and Cellular Cardiology. 18:983-991
Publication Year :
1986
Publisher :
Elsevier BV, 1986.

Abstract

Glutathione peroxidase activity with both hydrogen peroxide and cumene hydroperoxide was measured in the cytosolic fractions prepared from five human hearts obtained from post-mortem victims. In all the samples the activity with cumene hydroperoxide was higher than that obtained with hydrogen peroxide, suggesting that the selenium-independent glutathione peroxidase could also be present in this tissue. To determine its presence in heart tissue we fractionated the cardiac cytosol fraction on a column of Sephadex G-100 and measured glutathione peroxidase activity with both the substrates. Glutathione transferase activity was measured with 1-chloro-2,4-dinitrobenzene in the fractionated cytosol. The results indicated that a selenium-independent glutathione peroxidase activity was present (about 30% of total activity). Fractionation of the cytosol by gel filtration showed that peroxidase activity co-eluted with glutathione transferase activity. Subsequently the fractions containing glutathione transferase and selenium-independent glutathione peroxidase activity obtained from gel filtration experiments were passed through an affinity column and analyzed by isoelectric focusing. It was found that the selenium-independent glutathione peroxidase copurified with three isoenzymes of glutathione transferase which had a pI of 9.2, 8.9 and 8.6 respectively. In contrast the acidic isoenzymes of glutathione transferase lacked peroxidase activity. It is suggested that the selenium-independent glutathione peroxidase may play an important role in neutralizing oxygen toxicity in heart when the selenium-dependent glutathione peroxidase activity is impaired.

Details

ISSN :
00222828
Volume :
18
Database :
OpenAIRE
Journal :
Journal of Molecular and Cellular Cardiology
Accession number :
edsair.doi.dedup.....df41f50546e05ac7b7bce8e83fcb5d1c