Glutathione disulfide (GSSG) is a disulfide derived from two glutathione molecules.[1]

In living cells, glutathione disulfide is reduced into two molecules of glutathione with reducing equivalents from the coenzyme NADPH. This reaction is catalyzed by the enzyme glutathione reductase.[2] Antioxidant enzymes, such as glutathione peroxidases and peroxiredoxins, generate glutathione disulfide during the reduction of peroxides such as hydrogen peroxide (H2O2) and organic hydroperoxides (ROOH):[3]

2 GSH + ROOH → GSSG + ROH + H2O

Other enzymes, such as glutaredoxins, generate glutathione disulfide through thiol-disulfide exchange with protein disulfide bonds or other low molecular mass compounds, such as coenzyme A disulfide or dehydroascorbic acid.[4]

2 GSH + R-S-S-R → GSSG + 2 RSH

Neuromodulator

GSSG, along with glutathione and S-nitrosoglutathione (GSNO), have been found to bind to the glutamate recognition site of the NMDA and AMPA receptors (via their γ-glutamyl moieties), and may be endogenous neuromodulators.[5][6] At millimolar concentrations, they may also modulate the redox state of the NMDA receptor complex.[6]

See also

References

  1. ^ Meister A, Anderson M (1983). "Glutathione". Annu Rev Biochem. 52: 711–60. doi:10.1146/annurev.bi.52.070183.003431. PMID 6137189. 
  2. ^ Deneke SM, Fanburg BL (October 1989). "Regulation of cellular glutathione". Am. J. Physiol. 257 (4 Pt 1): L163–73. PMID 2572174. 
  3. ^ Meister A (1988). "Glutathione metabolism and its selective modification" (PDF). J Biol Chem. 263 (33): 17205–8. PMID 3053703. 
  4. ^ Holmgren A, Johansson C, Berndt C, Lönn ME, Hudemann C, Lillig CH (December 2005). "Thiol redox control via thioredoxin and glutaredoxin systems". Biochem. Soc. Trans. 33 (Pt 6): 1375–7. doi:10.1042/BST20051375. PMID 16246122. 
  5. ^ Steullet, P.; Neijt, H.C.; Cuénod, M.; Do, K.Q. (2006). "Synaptic plasticity impairment and hypofunction of NMDA receptors induced by glutathione deficit: Relevance to schizophrenia". Neuroscience. 137 (3): 807–819. doi:10.1016/j.neuroscience.2005.10.014. ISSN 0306-4522. 
  6. ^ a b Varga, V.; Jenei, Zs.; Janáky, R.; Saransaari, P.; Oja, S. S. (1997). "Glutathione Is an Endogenous Ligand of Rat Brain N-Methyl-D-Aspartate (NMDA) and 2-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionate (AMPA) Receptors". Neurochemical Research. 22 (9): 1165–1171. doi:10.1023/A:1027377605054. ISSN 0364-3190.