Mechanistic Characterization of a 2-Thioxanthine Myeloperoxidase Inhibitor and Selectivity Assessment Utilizing Click Chemistry–Activity-Based Protein Profiling
作者:Jessica Ward、Samantha N. Spath、Brandon Pabst、Philip A. Carpino、Roger B. Ruggeri、Gang Xing、Anna E. Speers、Benjamin F. Cravatt、Kay Ahn
DOI:10.1021/bi401354d
日期:2013.12.23
characterization demonstrating that A possesses all the distinguishing features of a mechanism-based inactivator. A is a time-dependent MPO inhibitor and displays saturable inactivation kinetics consistent with a two-step mechanism of inactivation and a potency (kinact/KI ratio) of 8450 ± 780 M–1 s–1. MPO inactivation by A is dependent on MPO catalysis and is protected by substrate. A reduces MPO compound
髓过氧化物酶(MPO)是一种血红素过氧化物酶,可催化次氯酸的产生。尽管对MPO作为治疗靶标有很高的兴趣,但是关于在药理学研究中适合评估MPO的MPO抑制剂的报道很少。最近有报道称2-硫代黄嘌呤3-(2-乙氧基丙基)-2-thioxo-2,3-二氢-1 H-嘌呤-6(9 H)-one(A)通过共价修饰血红素来抑制MPO义肢组。在这里,我们报告详细的机械表征,证明A拥有基于机制的灭活剂的所有显着特征。一种是时间依赖性的MPO抑制剂,显示出可饱和的失活动力学,与两步失活机理相符,效价(k inact / K I比)为8450±780 M –1 s –1。A使MPO失活取决于MPO催化并受底物保护。A将MPO化合物I还原为化合物II,其二级速率常数为(0.801±0.056)×10 6 M –1 s –1,其不可逆的MPO失活发生在释放激活的抑制物之前。尽管它对包括酶,受体,转运蛋白和离子通道在内