Cytochrome P450 (CYP) 3A5 characterized with polymorphic and extensive expression in multiple tissues is the most important P450 enzyme among the minor CYP3A isoforms. However, a selective and sensitive probe for CYP3A5 remains unavailable. In this study, we identified and characterized a naturally occurring lignan 12 (schisantherin E) as an isoform-specific probe for selective detection of CYP3A5 activity in complex biological samples. With thorough characterization including LC-MS and NMR, we found that 12 can be metabolized by CYP3A5 to generate a major metabolite 2-O-demethylated 12. Meanwhile, both reaction phenotyping and chemical inhibition experiments further revealed that CYP3A5 selectively catalyzed the 2-O-demethylation of 12. Specifically, the interactions between the Phe210 residue of CYP3A5 and methyl benzoate of 12 might play key roles in 12-O-demethylation, which was revealed by docking simulation and site-directed mutagenesis studies. These findings are beneficial for exploring the role of CYP3A5 in drug metabolism and pathologic process.
[1]Chinese Acad Sci, Dalian Inst Chem Phys, Dalian 116023, Peoples R China.
[2]Key Lab Liaoning Tumor Clin Metabol, Jinzhou, Liaoning, Peoples R China.
[3]Zunyi Med Univ, Minist Educ, Key Lab Basic Pharmacol, Sch Pharm, Zunyi 563000, Guizhou, Peoples R China.
[4]Univ Illinois, Dept Biopharmaceut Sci, Chicago, IL 60612 USA.
[5]Dalian Jiaotong Univ, Sch Environm & Chem Engn, Dalian 116028, Peoples R China.
[6]Shanghai Univ Tradit Chinese Med, Shanghai 201203, Peoples R China.
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