Bioactivation of <i>S</i>-(2,2-Dihalo-1,1-difluoroethyl)-<scp>l</scp>- cysteines and <i>S</i>-(Trihalovinyl)-<scp>l</scp>-cysteines by Cysteine S-Conjugate β-Lyase: Indications for Formation of both Thionoacylating Species and Thiiranes as Reactive Intermediates
作者:Jan N. M. Commandeur、Laurence J. King、Luc Koymans、Nico P. E. Vermeulen
DOI:10.1021/tx960049b
日期:1996.1.1
19F-NMR and GC-MS analysis. beta-Elimination reactions were performed using rat renal cytosol and a beta-lyase model system, consisting of pyridoxal and copper(II) ion. S-(1,1,2,2-Tetrafluoroethyl)-L-cysteine (TFE-Cys) was mainly converted to products derived from difluorothionoacetyl fluoride, namely, difluorothionoacetic acid, difluoroacetic acid, and N-difluorothionoacetylated TFE-Cys. In the presence
使用19F-NMR和GC-MS分析研究了通过卤代烯烃的半胱氨酸S-共轭物的β-消除形成的反应性中间体与亲核试剂的共价结合。使用大鼠肾细胞溶质和β-裂解酶模型系统(由吡ido醛和铜(II)离子组成)进行β-消除反应。S-(1,1,2,2-四氟乙基)-L-半胱氨酸(TFE-Cys)主要转化为衍生自二氟硫代乙酰氟的产物,即二氟硫代乙酸,二氟乙酸和N-二氟硫代乙酰化的TFE-Cys。在邻苯二胺(OPD)的存在下,作为双功能亲核捕获剂,形成的主要产物是2-(二氟甲基)苯并咪唑。该产物是由二氟硫代乙酰氟与OPD的一个氨基的初始反应产生的,然后在硫代酰基和OPD的相邻氨基之间发生缩合反应。与S-(2-氯-1,1,2-三氟氟乙基)-L-半胱氨酸(CTFE-Cys)和S-(2,2-二氯-1,1-二氟氟乙基)-L-半胱氨酸(DCDFE-还通过GC-MS分析观察到硫代酰基化的半胱氨酸S-缀合物的形成,表明形成了相应的硫代酰基氟。然而,根据19