page_title: S-Nitrosoglutathione
section_title: GSNOR
hierarchical_section_title: S-Nitrosoglutathione / GSNOR
caption_attribution_description: English: GSNO chemical reaction
context_page_description: S-Nitrosoglutathione is an endogenous S-nitrosothiol that plays a critical role in nitric oxide signaling and is a source of bioavailable NO. NO coexists in cells with SNOs that serve as endogenous NO carriers and donors. SNOs spontaneously release NO at different rates and can be powerful terminators of free radical chain propagation reactions, by reacting directly with ROO• radicals, yielding nitro derivatives as end products. NO is generated intracellularly by the nitric oxide synthase family of enzymes: nNOS, eNOS and iNOS while the in vivo source of many of the SNOs is unknown. In oxygenated buffers, however, formation of SNOs is due to oxidation of NO to dinitrogen trioxide. Some evidence suggests that both exogenous NO and endogenously derived NO from nitric oxide synthases can react with glutathione to form GSNO.
context_section_description: The enzyme GSNO reductase (GSNOR) reduces S-nitrosoglutathione (GSNO) to an unstable intermediate, S-hydroxylaminoglutathione, which then rearranges to form glutathione sulfonamide, or in the presence of GSH, forms oxidized glutathione (GSSG) and hydroxylamine.  Through this catabolic process, GSNOR regulates the cellular concentrations of GSNO and plays a central role in regulating the levels of endogenous S-nitrosothiols and controlling protein S-nitrosylation-based signaling.
  The generation of GSNO can serve as a stable and mobile NO pool which can effectively transduce NO signaling.  Unlike other low molecular weight messengers that bind to and activate target cellular receptors, NO signaling is mediated by a coordinating complex between NO and transition metals or target cellular proteins, often via S-nitrosylation of cysteine residues. Studies suggest that NO metabolism has a significant role in human cardiovascular and respiratory diseases as well as in immune tolerance during organ transplantation.
caption: The chemical synthesis of GSNO
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