Interaction of sulfaphenazole derivatives with human liver cytochromes P450 2C: molecular origin of the specific inhibitory effects of sulfaphenazole on CYP 2C9 and consequences for the substrate binding site topology of CYP 2C9.
Interaction of sulfaphenazole derivatives with human liver cytochromes P450 2C: molecular origin of the specific inhibitory effects of sulfaphenazole on CYP 2C9 and consequences for the substrate binding site topology of CYP 2C9.
复制标题
磺胺苯唑衍生物与人肝细胞色素 P450 2C 的相互作用：磺胺苯唑对 CYP 2C9 特异性抑制作用的分子起源以及对 CYP 2C9 底物结合位点拓扑的影响。
作者：
A. Mancy;S. Dijols;S. Poli;F. Guengerich;D. Mansuy
研究了磺胺苯吡唑对酵母表达的1A、3A和2C亚家族的人细胞色素P450催化的典型活性的影响。1作为一种强的竞争性抑制剂，抑制α 2C 9（K（i）= 0.3 +/- 0.1 μ M）;它对α 2C 8和2C 18的作用要弱得多（K（i）分别为63和29 μ M），并且不能抑制α 1A 1，1A 2，3A 4和2C 19。根据使用表达各种人P450的酵母微粒体的差异可见光谱实验，1选择性地仅与P450 Fe（III）-含氮配体复合物（Ks = 0.4 +/-0.1 microM）形成预期的在429 nm处出现峰的P450 Fe（III）-含氮配体复合物（Ks = 0.4 +/-0.1 microM）发生相互作用。对12个化合物的光谱相互作用和抑制作用的比较研究表明，1的苯胺官能团是429 nm-吸收复合物的铁氮键形成的原因，是1抑制作用的必要条件。在这项工作中合成的两种新化合物的研究，其中1的N-苯基被乙基或3，4-二氯苯基取代，表明在1的吡唑官能团的1位上存在疏水取代基是与N2 C9强相互作用所必需的。提出了一种1在β 2C 9活性位点结合的模型;该模型考虑了3种主要的相互作用，这些相互作用应该是1对β 2C 9的高亲和力和特异性抑制作用的起源：（ii）其SO 2N-阴离子位点与H2 C9的阳离子残基的离子相互作用，和（iii）其N-苯基与蛋白质活性位点的疏水部分的相互作用。
The effects of sulfaphenazole, 1, on typical activities catalyzed by human cytochromes P450 of the 1A, 3A, and 2C subfamilies expressed in yeast were studied. 1 acts as a strong, competitive inhibitor of CYP 2C9 (K(i) = 0.3 +/- 0.1 microM); it is much less potent toward CYP 2C8 and 2C18 (K(i) = 63 and 29 microM, respectively) and fails to inhibit CYP 1A1, 1A2, 3A4, and 2C19. From difference visible spectroscopy experiments using microsomes of yeast expressing various human P450s, 1 selectively interacts only with CYP 2C9 with the appearance of a peak at 429 nm as expected for the formation of a P450 Fe(III)-nitrogenous ligand complex (Ks = 0.4 +/- 0.1 microM). Comparative studies of the spectral interaction and inhibitory effects of twelve compounds related to 1 with CYP 2C9 showed that the aniline function of 1 is responsible for the formation of the iron-nitrogen bond of the 429 nm-absorbing complex and is necessary for the inhibitory effects of 1. The study of two new compounds synthesized during this work, in which the N-phenyl group of 1 was replaced with either an ethyl group or a 3,4-dichlorophenyl group, showed that the presence of an hydrophobic substituent at position 1 of the pyrazole function of 1 is required for a strong interaction with CYP 2C9. A model for the binding of 1 in the CYP 2C9 active site is proposed; that takes into account three major interactions that should be at the origin of the high-affinity and specific inhibitory effects of 1 toward CYP 2C9: (i) the binding of its nitrogen atom to CYP 2C9 iron, (ii) an ionic interaction of its SO2N- anionic site with a cationic residue of CYP 2C9, and (iii) an interaction of its N-phenyl group with an hydrophobic part of the protein active site.