HCV-NS3 inhibitors: Determination of their kinetic parameters and mechanism
HCV-NS3 inhibitors: Determination of their kinetic parameters and mechanism
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DOI：
10.1016/j.bbapap.2009.06.004
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发表时间：
2009-10-01
影响因子：
3.2
通讯作者：
Corbau, Romuald
中科院分区：
文献类型：
--
作者：
Flores, Maria Victoria;Strawbridge, Joanne;Corbau, Romuald
现有的丙型肝炎病毒蛋白水解酶抑制剂分为两类：可逆性和非共价性，如BILN-2061；共价性和可逆性，如SCH-503034和VX-950。在这项工作中，描述了这三种抑制剂的动力学特性。SCH-503034和VX-950最初与1b型丙型肝炎病毒NS3/4A蛋白水解酶结合形成低亲和力的复合体，其K-I值分别为5和5.8µM。这两个化合物形成第二个共价络合物(EL*)的能力导致了效力的增加，总的K-I*值分别为20和45 nm。药效的提高可以用它们缓慢的解离速度来解释，形成半衰期分别为2小时(VX-950)和5小时(SCH-503034)的络合物。尽管BILN-2061被描述为一种快速可逆的非共价缓蚀剂，但我们的结果显示了缓慢结合的两步机制。与SCH-503034和VX-950相反，BILN-2061可以形成高亲和力的第一络合物，其KI值为3.9W，总K-I*为0.14 nm。BILN-2061EI*络合物的半衰期比其他两种化合物的半衰期短(t(1/2)类似于0.7h)。结果表明，SCH-503034和VX-950相对于基因1的活性丧失主要是由于EL*复合体形成的开启速率较慢，关闭速率较快。在BILN-2061的情况下，使用一步模型获得了更好的拟合，表明效力的丧失是由于EL复合体的关闭速率增加所致。(C)2009爱思唯尔B.V.保留所有权利。
Existing HCV protease inhibitors fall into two categories: reversible and non-covalent, such as BILN-2061, and covalent and reversible, exemplified by SCH-503034 and VX-950. In this work, the characterization of the kinetics of these three inhibitors is presented. SCH-503034 and VX-950 initially bind to the genotype 1b HCV NS3/4A protease to form a low affinity complex, with K-i values of 5 and 5.8 mu M respectively. The ability of those two compounds to form a second covalent complex (El*) results in a potency increase, with overall K-i* values of 20 and 45 nM, respectively. The increase in potency can be explained by their slow dissociation rate, forming complexes with half-lives of 2 h (VX-950) and 5 h (SCH-503034). Although BILN-2061 has been described as a fast reversible, non-covalent inhibitor, our results show a slow binding two-step mechanism. Contrary to SCH-503034 and VX-950, BILN-2061 can form a high affinity first complex with a Ki value of 3.9 W and an overall K-i* of 0.14 nM. The half-life of the BILN-2061 EI* complex is shorter (t(1/2) similar to 0.7 h) than that of the other two compounds. The potency of these compounds is genotype dependent, and a kinetic analysis using NS3/4A from genotype 3a indicates that the loss of potency of SCH-503034 and VX-950 relative to genotype 1 is mainly due to the slow on-rate and faster off-rate for the formation of the El* complex. In the case of BILN-2061, a better fit is obtained using a one-step model, indicating that the loss of potency is due to an increase in the off-rate of the El complex. (C) 2009 Elsevier B.V. All rights reserved.