Formation of nitrosothiols from gaseous nitric oxide at pH 7.4

✍ Scribed by Carlo Alberto Palmerini; Carla Saccardi; Giuseppe Arienti; Roberto Palombari

• Book ID: 102303658
• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 175 KB
• Volume: 16
• Category: Article
• ISSN: 1095-6670
• DOI: 10.1002/jbt.10028

✦ Synopsis

Nitric oxide (NO) is generated in biological systems and plays important roles as a regulatory molecule. Its ability to bind to haem iron is well known. Moreover, it may lose an electron, forming the nitrosonium ion, involved in the synthesis of S-nitrosothiols (SNOs). It has been suggested that S-nitrosohaemoglobin (-SNO Hb) and low molecular weight SNOs may act as reservoirs of NO. SNOs are formed in vitro, at strongly acidic pH values; however, the mechanism of their formation at neutral pH values is still debated. In this paper we report the anaerobic formation of SNOs (both high- and low-molecular weight) from low concentrations of NO at pH 7.4, provided Hb is also present. We propose a reaction mechanism entailing the participation of Fehaem in the formation of NO(+) and the transfer of NO(+) either to Cysbeta(93) of Hb or to glutathione; we show that this reaction also occurs in human RBCs.