以咪达唑仑为探针，细胞色素P4503A4催化代谢过程机制的理论研究

细胞色素P4503A4（CYP3A4）是最重要的药物代谢酶。明确CYP3A4代谢药物的途径，阐明其与底物作用的复杂机制，对相关疾病的治疗和新药研发具有重要意义。生物体系内复杂反应发生的瞬时性及实验条件影响等问题，使得其代谢过程的微观机制尚不明确，制约了相关的实验研究深入开展。本项目拟以咪达唑仑（MDZ）为探针，结合已有实验结果，采用多尺度计算模拟策略对CYP3A4代谢MDZ的微观机制开展系统深入的理论研究。完善其三维结构模型，确定CYP3A4的底物结合位点、别构位点以及MDZ进入酶活性部位的通道，构建单底物和多底物的复合物模型，探究膜诱导的底物通道选择性机制，明确其代谢过程的具体作用机制及关键因素，总结其中各种微观效应协同作用和综合调控的规律，从分子水平阐明CYP3A4代谢MDZ过程的调控机制。本项目的研究成果将为P450酶系的相关实验探索和药物研发提供可靠的理论依据和引导。

Cytochrome P450 (CYP) isoform 3A4 (CYP3A4) is the most important enzyme for human drug metabolism. In order to improve the treatment of the related diseases and to enhance the development of new drugs, it is of great significance to determine the drug metabolic pathways and to understand the complex mechanism of interactions between CYP3A4 and substrates. Due to the transient nature of the complex reactions in biological systems and the influences of various experimental conditions, the microscopic mechanism of its metabolic process is still unclear, which has restricted the in-depth development of the related experimental research. Combined with the experimental results, our project will use midazolam (MDZ) as the probe and perform multiscale simulations to systematically study the mechanism of MDZ metabolism by CYP3A4. The proposal aims at refining the 3D structure of CYP3A4, identifying the substrate binding site, allosteric site and substrate channels, constructing the complex models of single-substrate and multi-substrates separately, exploring the selective mechanism of membrane-induced substrate channels, clarifying the specific mechanism and key factors in the metabolic process, summarizing the synergistic effects of various micro-effects and the rules of synthetical regulation, and elucidating the regulatory mechanism of MDZ metabolism by CYP3A4 at the molecular level. Our simulations will provide the reliable thereunder and new clue for the experimental and drug design of CYPs.