Construction of refined CYP2D6-Template system for studies of its metabolism and inhibition

The previously reported Template system for the prediction of human CYP2D6-mediated reactions (Drug Metab Dispos 40 486-96, 2012) has been refined with the introduction of ideas of allowable width, Trigger∗-residue and the residue-initiated movement of ligands in the active site. These ideas are in common with published Template systems for human CYP1A1, CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C18, CYP2C19, CYP2E1, CYP2J2, and CYP3A4/5/7 (Drug Metab Pharmacokinet 2016, 2019, 2020, 2021, 2022, 2023, and 2024, Food Safety 2024). Total 616 reactions of 441 distinct chemicals reported as CYP2D6 ligands were examined in the refined CYP2D6-Template system. From their placements on the refined Template and rules for interaction modes, verifications of good and poor substrates, regio/stereo-selectivity, and inhibition became faithfully available for these ligands. A comparison of the placements suggested key interactions with Shelf and Left-end for ligand accommodations on the refined CYP2D6-Template. Shelf-surrounding of ligands was also proposed as a cause of their intense inhibitions. The refined CYP2D6-Template system will thus offer reliable estimations of this human CYP catalyses toward ligands of diverse structures, together with their deciphering information to lead to judgments of regioselective metabolisms.