Cross-Linking of Proteins by 3-(Trifluoromethyl)-2,5-hexanedione. Model Studies Implicate an Unexpected Amine-Dependent Defluorinative Substitution Pathway Competing with Pyrrole Formation
作者:Guozhang Xu、Lawrence M. Sayre
DOI:10.1021/jo011101y
日期:2002.5.1
Protein modification by the neurotoxic gamma-diketone 3-methyl-2,5-hexanedione (3-MHD) and its analogue 3-(trifluoromethyl)-2,5-hexanedione (3-TFMHD) was examined. Unlike 3-MHD, which forms lysine-based pyrroles that lead to autoxidation-dependent protein cross-linking, 3-TFMHD forms an autoxidatively inert pyrrole. The surprising finding that 3-TFMHD was nonetheless as effective as 3-MHD in cross-linking
研究了神经毒性γ-二酮3-甲基-2,5-己二酮(3-MHD)及其类似物3-(三氟甲基)-2,5-己二酮(3-TFMHD)对蛋白质的修饰作用。与3-MHD形成基于赖氨酸的吡咯并导致自氧化依赖的蛋白质交联不同,3-TFMHD形成自氧化惰性的吡咯。3-TFFMD在交联核糖核酸酶A方面仍然与3-MHD一样有效,这一令人惊讶的发现表明,蛋白质赖氨酸与3-TFFMD的缩合可以替代与吡咯形成竞争的过程。使用新戊胺进行的模型研究导致分离出预期的1-(2,2-二甲基丙基)-2,5-二甲基-3-(三氟甲基)吡咯以及新戊胺-3-TFMHD 2:1加合物N,N' -双(2,2-二甲基丙基)-2-氨基-3-乙酰基-5-甲基吡咯(主要)和N,N'-双(2,2-二甲基丙基)-3-(1-氨基亚乙基)-5-甲基-4-吡咯啉-2-酮(次要)。提议通过席夫碱形成,烯胺氟化物消除,第二胺缩合和水解进行这些2:1加合物的形成,据认