Lee GH, Kim V, Lee SG, Jeong E, Kim C, Lee YB, Kim D. Catalytic enhancements in cytochrome P450 2C19 by cytochrome
b5.
Toxicol Res 2024;
40:215-222. [PMID:
38525137 PMCID:
PMC10959859 DOI:
10.1007/s43188-023-00219-8]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/31/2023] [Accepted: 11/23/2023] [Indexed: 03/26/2024] Open
Abstract
Human cytochrome P450 2C19 catalyzes P450 enzyme reactions of various substrates, including steroids and clinical drugs. Recombinant P450 2C19 enzyme with histidine tag was successfully expressed in Escherichia coli and purified using affinity column chromatography. Ultra-performance liquid chromatography-tandem mass (UPLC-MS/MS) spectrometry showed that the purified P450 2C19 enzyme catalyzed 5-hydroxylation reaction of omeprazole. The purified enzyme displayed typical type I binding spectra to progesterone with a Kd value of 4.5 ± 0.2 µM, indicating a tight substrate binding. P450 2C19 catalyzed the hydroxylation of progesterone to produce 21-hydroxy (OH) as a major and 17-OH product as a minor product. Steady-state kinetic analysis of progesterone 21-hydroxylation indicated that the addition of cytochrome b5 stimulated a five-times catalytic turnover number of P450 2C19 with a kcat value of 1.07 ± 0.08 min-1. The molecular docking model of progesterone in the active site of P450 2C19 displayed that the 21-carbon of progesterone was located close to the heme with a distance of 4.7 Å, suggesting 21-hydroxylation of progesterone is the optimal reaction of P450 2C19 enzyme for a productive orientation of the substrate. Our findings will help investigate the extent to which cytochrome b5 affects the metabolism of P450 2C19 to drugs and steroids.
Supplementary Information
The online version contains supplementary material available at 10.1007/s43188-023-00219-8.
Collapse