Sulfur-to-nitrogen transnitrosation: transfer of nitric oxide from S-nitroso compounds to diethanolamine and the role of intermediate sulfur-to-sulfur transnitrosation.
S-Nitrosothiols are formed in vivo and are involved in NO signaling. We investigated the sulfur-to-nitrogen transnitrosation activity of S-nitrosocysteine, S-nitrosoglutathione, S-nitrosohomocysteine, S-nitrosocysteinylglycine and S-nitroso-N-acetylcysteine in their reaction with the secondary amine diethanolamine in vitro. The resulting N-nitrosodiethanolamine, a strong carcinogen, was formed in yields of up to 11% from S-nitrosocysteine and S-nitrosocysteinylglycine, whereas the transnitrosation activity of the other S-nitroso compounds was weak. However, the addition of L-cysteine to a solution of S-nitrosohomocysteine and diethanolamine accelerated the decomposition of S-nitrosohomocysteine and resulted in a significant formation of N-nitrosodiethanolamine accompanied by the intermediate generation of S-nitrosocysteine. Thus, reactive nitrosothiols can be formed from less reactive analogs via sulfur-to-sulfur transnitrosation. We suggest that this affects regulation of NO trafficking in vivo. The reaction provides an alternative mechanism for the generation of carcinogenic N-nitroso derivatives.
Al-Mustafa
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AH
Institut für Physiologische Chemie I, Heinrich-Heine-Universität Düsseldorf, Postfach 101007, D-40001 Düsseldorf, Germany.
Sies
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Stahl
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D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives / Q000737:chemistry; D004983:Ethanolamines / Q000737:chemistry*; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000737:chemistry; D009566:Nitrates / Q000737:chemistry; D009569:Nitric Oxide / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D015538:Nitrosation; D009603:Nitroso Compounds / Q000737:chemistry*; D026403:S-Nitrosothiols; D015398:Signal Transduction; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry*; D013997:Time Factors
D004983:Ethanolamines; D009566:Nitrates; D009603:Nitroso Compounds; D026403:S-Nitrosothiols; C417091:S-nitrosocysteinylglycine; D013438:Sulfhydryl Compounds; D006710:Homocysteine; C079202:S-nitrosohomocysteine; C039642:peroxynitric acid; D009569:Nitric Oxide; D013455:Sulfur; C021315:S-nitrosocysteine; C020283:diethanolamine; D003545:Cysteine; D009584:Nitrogen