Inhibition of cytochrome P450 (CYP)‐mediated drug metabolism by dietary substances is the main cause of drug–food interactions in humans. The present study reports on the in vitro inhibition assays of human CYP3A4 genetically linked to the reductase domain of bacterial BM3 of Bacillus megaterium (BMR) resulting in the chimeric protein CYP3A4–BMR. The activity of this chimeric enzyme was initially measured colorimetrically with erythromycin as the substrate where K_M values similar to published data were determined. Subsequently, the inhibition assays with three different dietary products, grapefruit juice, curcumin, and resveratrol, were carried out with the chimeric enzyme both in solution and immobilized on electrode surfaces. For the solution studies, nicotinamide adenine dinucleotide phosphate was added as the electron donor, whereas the need for this cofactor was obviated in the immobilized enzyme as it was supplied by the electrode. Inhibition of the N‐demethylation of erythromycin by CYP3A4–BMR chimera was measured at increasing concentrations of the different dietary compounds with calculated IC₅₀ values of 0.5%, 31 μM, and 250 μM for grapefruit juice, curcumin, and resveratrol measured in solution compared with 0.7%, 24 μM, and 208 μM measured electrochemically, respectively. These data demonstrate the feasibility of the use of both CYP3A4–BMR chimera as well as bioelectrochemistry for in vitro studies of not only drug–food interactions but also prediction of adverse drug reactions in this important P450 enzyme.

中文翻译：

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嵌合细胞色素P450 3A4用于体外预测食物与药物的相互作用。

饮食物质对细胞色素P450（CYP）介导的药物代谢的抑制是人类药物与食物相互作用的主要原因。本研究报告了人类CYP3A4的体外抑制测定，该测定与巨大芽孢杆菌（BMR）细菌BM3的还原酶结构域遗传相关，从而产生了嵌合蛋白CYP3A4-BMR。最初以红霉素为底物比色法测定该嵌合酶的活性，其中K _M确定与公开数据相似的值。随后，用嵌合酶在溶液中固定在电极表面上，用三种不同的饮食产品（葡萄柚汁，姜黄素和白藜芦醇）进行抑制试验。为了进行溶液研究，添加了烟酰胺腺嘌呤二核苷酸磷酸作为电子供体，而固定化酶不再需要这种辅因子，因为它是由电极提供的。CYP3A4–BMR嵌合体对红霉素的N-去甲基化的抑制作用是在不同饮食化合物的浓度增加的情况下通过IC ₅₀计算得出的溶液中葡萄柚汁，姜黄素和白藜芦醇的浓度分别为0.5％，31μM和250μM，而电化学法分别为0.7％，24μM和208μM。这些数据证明了同时使用CYP3A4–BMR嵌合体和生物电化学技术进行体外研究的可行性，该研究不仅涉及药物与食物之间的相互作用，而且还预测了该重要P450酶中的药物不良反应。