radical; comparison with the peroxynitrite reaction![Sample our Food Science & Technology journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5936/TOC-Subject-Sample-2021-Food-Science-Technology.jpg"})
Abstract
N-nitroso species have recently been detected in animal tissues. Protein N-nitrosotryptophan is the best candidate for this N-nitroso pool. N-nitrosation of N-blocked trytophan derivatives like melatonin (MelH) by N2O3 or peroxynitrite (ONOOH/ONOO− ) has been observed under conditions of pH and reagent concentrations similar to in vivo conditions. We studied the reaction of with MelH. When
was synthesized by γ-irradiation of aqueous neutral solutions of nitrate under anaerobic conditions, detected oxidation and nitration of MelH were negligible. In the presence of additional nitrite, when NO√ was also generated, formation of 1-nitrosomelatonin increased with nitrite concentration. Nitrosation is not due to N2O3 but could proceed via successive additions of
and NO√. For comparison, peroxynitrite was infused into a solution of MelH under air leading to the same products as those detected in irradiated solutions but in different proportions. In the presence of additional nitrite, the formation of nitroderivatives increased significantly while N-formylkynuramine and 1-nitrosomelatonin were maintained at similar levels. Mechanistic implications are discussed.
| Abbreviations | ||
| MelH | = | melatonin |
| MelNO | = | 1-nitrosomelatonin |
| MelNO2 | = | nitromelatonin |
| Abbreviations | ||
| MelH | = | melatonin |
| MelNO | = | 1-nitrosomelatonin |
| MelNO2 | = | nitromelatonin |