Dealkylation of quaternary ammonium salts by thiolate anions: A model of the cobalamin-independent methionine synthase reaction.
作者:Ellen Hilhorst、Tjoe B.R.A. Chen、Atef S. Iskander、Upendra K. Pandit
DOI:10.1016/s0040-4020(01)85267-4
日期:1994.1
The reactions of thiolate ions derived from thiophenol and homocysteine with substituted quaternary ammonium salts result in alkyl transfer from nitrogen to sulfur. A radical mechanism for this transalkylation, accounts for the reactivity pattern of the substrate salts. In a model study of the cobalamin-independent methionine synthase reaction, 5,5,6,7-tetramethyl-5,6,7,8-tetrahydropteridinium salt
衍生自硫酚和高半胱氨酸的硫醇根离子与取代的季铵盐的反应导致烷基从氮转移到硫。这种烷基转移的自由基机理解释了底物盐的反应模式。在不依赖钴胺素的蛋氨酸合酶反应的模型研究中,可以将5,5,6,7-四甲基-5,6,7,8-四氢opter啶鎓盐(25)视为天然辅酶5的模型。使CH 3 H 4-叶酸盐(1)与高半胱氨酸的硫醇盐反应,结果观察到蛋氨酸的形成具有良好的产率。这些结果表明,在酶促过程中,N(5)-CH 3 N(5)与亲电试剂或质子在活性位点的配位可激活甲基键的甲基键。