IMR Press / FBL / Volume 8 / Issue 1 / DOI: 10.2741/1032

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on as a courtesy and upon agreement with Frontiers in Bioscience.

Nitrosation of cysteine and reduced glutathione by nitrite at physiological pH
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1 Division of Science and Mathematics, Bethune-Cookman College, Daytona Beach, Florida 32114, USA
Front. Biosci. (Landmark Ed) 2003, 8(1), 62–69;
Published: 1 May 2003

Unlike the formation of nitrosothiols by nitrous acid, our study revealed that NO2- effectively reacted with L-cysteine or reduced glutathione (GSH) at pH 7.0 and 7.4, to form orange-pink products of S-nitrosocysteine (CySNO) or S-nitrosoglutathione (GSNO). The reactions were in a concentration-dependent manner. These products exhibited not only peak absorbances at around 340 and 540 nm, but also unique colors and patterns of mobility on cellulose thin layer chromatographic plates. In comparison, the S-nitrosation of dithiothreitol was noted exclusively under acidic pH. In addition, the S-nitrosation of hemoglobin (Hb) by either peroxynitrite (PN) or NO2- at pH 6.0 was detected via Western blot. The half-life of degradation of CySNO in NO2- solution was significantly shorter than that of GSNO at a wide range of pH. In the absence of NO2-, degradation of GSNO was facilitated by incubation with L-cysteine, but not L-serine. In the signaling process involving NO → PN → NO2- → CySNO/GSNO → NO, L-cysteine may function as a NO-carrier to reach shorter-distance targets, and also an "activator" to release NO from GSNO. Furthermore, L-cysteine may play a vital role in reducing (severe) oxidative stress.

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