化学
亚硝化
加合物
醌
邻氨基苯甲酸
代谢物
有机化学
激进的
亚硝酸盐
药物化学
生物化学
硝酸盐
作者
Claudia Backhaus,Hafizur Rahman,Sebastian Scheffler,Hartmut Laatsch,Rüdiger Hardeland
出处
期刊:Nitric Oxide
[Elsevier]
日期:2008-11-01
卷期号:19 (3): 237-244
被引量:25
标识
DOI:10.1016/j.niox.2008.07.002
摘要
The tryptophan metabolites kynurenine, 3-hydroxykynurenine, anthranilic, 3-hydroxyanthranilic and 3-methoxyanthranilic acids were compared with regard to diazotation by ·NO or NO+, using three different donors, nitrite at pH 5, PAPA-NONOate at pH 7.4 and NO+SbF6− at pH 2.0. With all three sources of NO species, 3-hydroxykynurenine and 3-hydroxyanthranilic acid were readily nitrosated, thereby forming an intensely yellow compound. Nitrosation of the non-hydroxylated analogs did not lead to colored products within the period of observation. Competition experiments, using PAPA-NONOate as NO donor, showed that 3-hydroxyanthranilic acid is a more potent NO scavenger than N-acetylcysteine. Nitrosation of 3-hydroxykynurenine and 3-hydroxyanthranilic acid leads, presumably via a nitrosamine intermediate, to a diazonium ion, which forms an oxadiazole tautomerizing to a yellow o-quinone diazide. While the diazonium-derived quinone diazide is apparently the sole product detected directly after incubation of 3-hydroxyanthranilic acid, additional substances are formed from 3-hydroxykynurenine. Contrary to rapid carbenium ion formation from diazonium ions of non-hydroxylated anilines, nitrogen is practically not released from oxadiazoles/quinone diazides at moderate temperatures. Since carbenium ions are known to cause adduct formation with other biomolecules, and since non-hydroxylated anilines and their aminophenol analogs differ in their reactions following diazotation, these findings should be of relevance for the relative toxicity of anilines.
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