Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita 565-0871, Japan; Analytical Chemistry Department, Faculty of Pharmacy, Minia University, Minia, Egypt.
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita 565-0871, Japan.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Feb 15;209:209-216. doi: 10.1016/j.saa.2018.10.045. Epub 2018 Oct 26.
Cytochrome P450 (CYP) is a class of heme-containing enzymes which mainly catalyze a monooxygenation reaction of various chemicals, and hence CYP plays a key role in the drug metabolism. Although CYP2C19 isoform is a minor hepatic CYP, it metabolizes clinically important drugs such as omeprazole and S‑mephenytoin. In this work, the interaction of purified CYP2C19 WT (CYP2C19) with seven drugs (phenytoin, S‑mephenytoin, omeprazole, lansoprazole, cimetidine, propranolol, and warfarin) was investigated using spectroscopic methods. The binding of each drug and the induced structural change in the heme distal environment were evaluated. Ferric form of CYP2C19 was revealed to contain a six-coordinate low-spin heme with a water molecule as a sixth ligand in a distal site, and the addition of each drug caused varied minor fraction of five-coordinate heme. It was suggested that the ligated water molecule was partly moved away from the heme distal environment and that the degree of water removal was dependent on the type of drugs. The effect on the coordination was varied with the studied drugs with wide variation in the dissociation constants from 2.6 μM for lansoprazole to 5400 μM for warfarin. Phenytoin and S‑mephenytoin showed that binding to CYP2C19 occurred in a stepwise manner and that the coordination of a water molecule was facilitated in the second binding step. In the ferrous CO-bound state, ν(FeCO) stretching mode was clearly observed at 471 cm in the absence of drugs. The Raman line was greatly up-shifted by omeprazole (487 cm) and lansoprazole (477 cm) but was minimally affected by propranolol, phenytoin, and S‑mephenytoin. These results indicate that slight chemical modification of a drug greatly affects the heme distal environments upon binding.
细胞色素 P450（CYP）是一类含有血红素的酶，主要催化各种化学物质的单加氧反应，因此 CYP 在药物代谢中起着关键作用。虽然 CYP2C19 同工酶是一种次要的肝 CYP，但它代谢临床上重要的药物，如奥美拉唑和 S-美芬妥因。在这项工作中，使用光谱方法研究了纯化的 CYP2C19 WT（CYP2C19）与七种药物（苯妥英、S-美芬妥因、奥美拉唑、兰索拉唑、西咪替丁、普萘洛尔和华法林）的相互作用。评估了每种药物的结合及其在血红素远端环境中引起的结构变化。发现铁形式的 CYP2C19 含有一个六配位低自旋血红素，在远端位置有一个水分子作为第六配体，每种药物的加入都会导致少量五配位血红素。这表明连接的水分子部分从血红素远端环境中移出，并且水的去除程度取决于药物的类型。与研究的药物相比，这种对配位的影响变化很大，从兰索拉唑的解离常数 2.6 μM 到华法林的 5400 μM 不等。苯妥英和 S-美芬妥英表明，与 CYP2C19 的结合是分步进行的，并且水分子的配位在第二步结合中得到促进。在亚铁 CO 结合态下，在没有药物的情况下，在 471 cm 处清楚地观察到 ν（FeCO）伸缩模式。奥美拉唑（487 cm）和兰索拉唑（477 cm）使拉曼线大大上移，但普萘洛尔、苯妥英和 S-美芬妥英的影响最小。这些结果表明，药物的轻微化学修饰在结合时会极大地影响血红素远端环境。
