Oxidation studies of a novel peptide model N-acetyl-3-(methylthio)propylamine
| Autor: | Tomasz Pedzinski, Piotr Filipiak, Franciszek Kazmierczak, Bronislaw Marciniak |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
Reaction mechanism 010405 organic chemistry General Chemical Engineering Dimer Radical General Physics and Astronomy Propylamine Sulfoxide General Chemistry 010402 general chemistry Photochemistry 01 natural sciences Medicinal chemistry 0104 chemical sciences chemistry.chemical_compound Deprotonation chemistry Radiolysis Alkyl |
| Zdroj: | Journal of Photochemistry and Photobiology A: Chemistry. 336:98-104 |
| ISSN: | 1010-6030 |
| DOI: | 10.1016/j.jphotochem.2016.12.032 |
| Popis: | The OH radical induced oxidation of a selected methionine analogue − N-acetyl-3-(methylthio)propylamine (N-acetylated methionine without its carboxylic group) was investigated in aqueous solution. The oxidized intermediate (>S +) can be stabilized by the formation of two-centered three-electron bonds with electron-rich atoms (S, N, O), or it can undergo deprotonation yielding the long-lived, carbon-centered α-(alkylthio)alkyl radical (αS). The paths and kinetics of these reactions were followed using the pulse radiolysis technique with spectrophotometric detection. The reaction mechanism is shown to be different from the mechanism previously reported for 3-(methylthio)propylamine (3-MTPA), and depends strongly on the structural nature of the methionine substituents. The oxidation of 3-AcMTPA by OH radicals in anaerobic conditions yielded a sulfoxide (>S O) and a stable dimer (αS–αS) formed from the combination of two α-(alkylthio)alkyl radicals as major stable products. The proposed mechanism is further supported by the stable product analysis carried out using a high-resolution LC–MS/MS technique. A detailed mechanism involving characterizations of the transients and the stable products is discussed in qualitative terms. It is clearly demonstrated that the results from the time-resolved investigations are consistent with the findings from the stable product analysis. |
| Databáze: | OpenAIRE |
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