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.

Fig. 1: The figure shows the general procedure for the synthesis and metabolism of glutathione. From glutamic acid (Glu) and cysteine (Cys) is created by the enzyme γ-synthase glutamylcystein (γ-ECS) γ-glutamylcystein (γ-Glu - Cys). The effect of the enzyme glutathione synthase (GSH-S) from γ-Glu-Cys and glycine (Gly) synthesized glutathione reduced form (GSH). As an antioxidant, GSH is oxidized to form oxidized glutathione (GSSG) with the participation of the enzyme glutathione peroxidase (GPO). Thanks to the action of glutathione reductase (GshR) glutathione occurs mainly in the form of GSH. Degradation of glutathione in cells is due to the γ-glutamyl transpeptidase (GGT) for glutamic acid (Glu) and dipeptide cysteinylglycine (Cys-Gly)

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