Damage of aromatic amino acids by the atmospheric free radical oxidant NO3˙ in the presence of NO2˙, N2O4, O3 and O2
作者:Catrin Goeschen、Natalia Wibowo、Jonathan M. White、Uta Wille
DOI:10.1039/c0ob01186j
日期:——
Analysis of the products formed in the reaction of NO3Ë with the N- and C-protected aromatic amino acids 1â5, which was performed under conditions that simulate exposure of biosurfaces to environmental pollutants, revealed insight how this important atmospheric free-radical oxidant can cause irreversible damage. In general, NO3Ë induced electron transfer at the aromatic ring is the exclusive initial pathway in a multi-step sequence, which ultimately leads to nitroaromatic compounds. In the reaction of NO3Ë with tryptophan 5 tricyclic products 12 and 13 are formed through an intramolecular, oxidative cyclization involving the amide moiety. In addition to this, strong indication for formation of N-nitrosamides was obtained, which likely result from reaction with N2O4 through an independent non-radical pathway.
在模拟生物表面暴露于环境污染物的条件下,对NO3Ë与N-和C-保护的芳香族氨基酸1â5反应形成的产物进行了分析,深入揭示了这种重要的大气自由基氧化剂如何造成不可逆的损害。一般来说,NO3Ë 在芳香环上诱导的电子转移是一个多步骤序列中唯一的初始途径,最终生成硝基芳香族化合物。在 NO3Ë 与色氨酸 5 的反应中,通过涉及酰胺分子的分子内氧化环化,形成了三环产物 12 和 13。除此之外,还得到了 N-亚硝基酰胺形成的强烈迹象,这可能是通过独立的非辐射途径与 N2O4 反应的结果。