The ratio of GSH/GSSG in biological organisms

Tripeptide glutathion is one of the most important thiol compound. It is involved in a wide variety of cellular processes. In the organism it occurs in two forms: as a reduced glutathion (GSH) and as an oxidized glutathion (GSSG). Protective and regulatory functions of GSH are based on changes in its redox state. GSH and GSSG forms together one of the most significant redox couples in the cell. Their ratio under the physiological conditions is usually constant, regardless of the total concentration of glutathion in a cell. The ratio of both forms of glutathion is considered as an indicator of oxidative stress effect.

Obr. 1: Na obrázku je zobrazen obecný postup syntézy a metabolismu glutathionu. Z kyseliny glutamové (Glu) a cysteinu (Cys) vzniká díky enzymu γ-glutamylcystein syntáza (γ-ECS) γ-glutamylcystein (γ-Glu- -Cys). Účinkem enzymu glutathion syntázy (GSH-S) se z γ-Glu-Cys a glycinu (Gly) syntetizuje glutathion v redukované formě (GSH). Jako antioxidant se GSH oxiduje na oxidovanou formu glutathionu (GSSG) za účasti enzymu glutathion peroxidázy (Gpo). Díky působení glutation reduktázy (GshR) se glutathion vyskytuje především ve formě GSH. K degradaci glutathionu v buňkách dochází díky γ-glutamyl transpeptidáze (GGT) na kyselinu glutamovou (Glu) a dipeptid cysteinylglycin (Cys-Gly)

1. De Rey-Pailhade, J. Sur un corps d’origine organique hydrogénant le soufre 1 à froid. Comptes Rendus Hebdomadaire Séances de l’Académie de Sciences. 1888, 1683–1684.
2. Meister, A. On the Biochemistry of Glutathione, Glutathione Centennial, 1989, pp. 3-21.
3. Pophaly, S.D.; Singh, R.; Kaushik, J.K.; Tomar, S.K. Current status and emerging role of glutathione in food grade lactic acid bacteria. Microbial Cell Factories. 2012, 11.
4. Seth, C.S.; Remans, T.; Keunen, E.; Jozefczak, M.; Gielen, H.; Opdenakker, K.; Weyens, N.; Vangronsveld, J.; Cuypers, A. Phytoextraction of toxic metals: a central role for glutathione. Plant Cell and Environment. 2012, 35, 334-346.
5. Paradiso, A.; Berardino, R.; de Pinto, M.C.; di Toppi, L.S.; Storelli, M.M.; Tommasi, F.; De Gara, L. Increase in ascorbate-glutathione metabolism as local and precocious systemic responses induced by cadmium in durum wheat plants. Plant and Cell Physiology. 2008, 49, 362-374.
6. Forman, H.J.; Zhang, H.Q.; Rinna, A. Glutathione: Overview of its protective roles, measurement, and biosynthesis. Molecular Aspects of Medicine. 2009, 30, 1-12.
7. Pastore, A.; Federici, G.; Bertini, E.; Piemonte, F. Analysis of glutathione: implication in redox and detoxification. Clinica Chimica Acta. 2003, 333, 19-39.
8. Biswas, S.K.; Rahman, I. Environmental toxicity, redox signaling and lung inflammation: The role of glutathione. Molecular Aspects of Medicine. 2009, 30, 60-76.
9. Anderson, M.E. Glutathione: an overview of biosynthesis and modulation. Chemico-Biological Interactions. 1998, 112, 1-14.
10. Ogawa, K. Glutathione-associated regulation of plant growth and stress responses. Antioxidants & Redox Signaling. 2005, 7, 973-981.
11. Szalai, G.; Kellos, T.; Galiba, G.; Kocsy, G. Glutathione as an Antioxidant and Regulatory Molecule in Plants Under Abiotic Stress Conditions. Journal of Plant Growth Regulation. 2009, 28, 66-80.
12. Noctor, G.; Veljovic-Jovanovic, S.; Driscoll, S.; Novitskaya, L.; Foyer, C.H. Drought and oxidative load in the leaves of C3 plants: a predominant role for photorespiration? Ann Bot. 2002, 89 Spec No, 841-850.
13. Valko, M.; Leibfritz, D.; Moncol, J.; Cronin, M.T.D.; Mazur, M.; Telser, J. Free radicals and antioxidants in normal physiological functions and human disease. International Journal of Biochemistry & Cell Biology. 2007, 39, 44-84.

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