Molecular docking and oxidation kinetics of 3-phenyl coumarin derivatives by human CYP2A13
Creators: name: Juvonen, Risto O.
name: Jokinen, Elmeri M.
name: Huuskonen, Juhani
name: Kärkkäinen, Olli
name: Raunio, Hannu
name: Pentikäinen, Olli T.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biophysics
subject: Biochemistry
subject: Pharmacology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Hematology
subject: 60506 Virology

description: CYP2A13 enzyme is expressed in human extrahepatic tissues, while CYP2A6 is a hepatic enzyme. Reactions catalysed by CYP2A13 activate tobacco-specific nitrosamines and some other toxic xenobiotics in lungs.To compare oxidation characteristics and substrate-enzyme active site interactions in CYP2A13 vs CYP2A6, we evaluated CYP2A13 mediated oxidation characteristics of 23 coumarin derivatives and modelled their interactions at the enzyme active site.CYP2A13 did not oxidise six coumarin derivatives to corresponding fluorescent 7-hydroxycoumarins. The K<sub>m</sub>-values of the other coumarins varied 0.85–97 µM, V<sub>max</sub>-values of the oxidation reaction varied 0.25–60 min<sup>−1</sup>, and intrinsic clearance varied 26–6190 kL/min*mol CYP2A13). K<sub>m</sub> of 6-chloro-3-(3-hydroxyphenyl)-coumarin was 0.85 (0.55–1.15 95% confidence limit) µM and V<sub>max</sub> 0.25 (0.23–0.26) min<sup>−1</sup>, whereas K<sub>m</sub> of 6-hydroxy-3-(3-hydroxyphenyl)-coumarin was 10.9 (9.9–11.8) µM and V<sub>max</sub> 60 (58–63) min<sup>−1</sup>. Docking analyses demonstrated that 6-chloro or 6-methoxy and 3-(3-hydroxyphenyl) or 3-(4-trifluoromethylphenyl) substituents of coumarin increased affinity to CYP2A13, whereas 3-triazole or 3-(3-acetate phenyl) or 3-(4-acetate phenyl) substituents decreased it.The active site of CYP2A13 accepts more diversified types of coumarin substrates than the hepatic CYP2A6 enzyme. New sensitive and convenient profluorescent CYP2A13 substrates were identified, such as 6-chloro-3-(3-hydroxyphenyl)-coumarin having high affinity and 6-hydroxy-3-(3-hydroxyphenyl)-coumarin with high intrinsic clearance. CYP2A13 enzyme is expressed in human extrahepatic tissues, while CYP2A6 is a hepatic enzyme. Reactions catalysed by CYP2A13 activate tobacco-specific nitrosamines and some other toxic xenobiotics in lungs. To compare oxidation characteristics and substrate-enzyme active site interactions in CYP2A13 vs CYP2A6, we evaluated CYP2A13 mediated oxidation characteristics of 23 coumarin derivatives and modelled their interactions at the enzyme active site. CYP2A13 did not oxidise six coumarin derivatives to corresponding fluorescent 7-hydroxycoumarins. The K<sub>m</sub>-values of the other coumarins varied 0.85–97 µM, V<sub>max</sub>-values of the oxidation reaction varied 0.25–60 min<sup>−1</sup>, and intrinsic clearance varied 26–6190 kL/min*mol CYP2A13). K<sub>m</sub> of 6-chloro-3-(3-hydroxyphenyl)-coumarin was 0.85 (0.55–1.15 95% confidence limit) µM and V<sub>max</sub> 0.25 (0.23–0.26) min<sup>−1</sup>, whereas K<sub>m</sub> of 6-hydroxy-3-(3-hydroxyphenyl)-coumarin was 10.9 (9.9–11.8) µM and V<sub>max</sub> 60 (58–63) min<sup>−1</sup>. Docking analyses demonstrated that 6-chloro or 6-methoxy and 3-(3-hydroxyphenyl) or 3-(4-trifluoromethylphenyl) substituents of coumarin increased affinity to CYP2A13, whereas 3-triazole or 3-(3-acetate phenyl) or 3-(4-acetate phenyl) substituents decreased it. The active site of CYP2A13 accepts more diversified types of coumarin substrates than the hepatic CYP2A6 enzyme. New sensitive and convenient profluorescent CYP2A13 substrates were identified, such as 6-chloro-3-(3-hydroxyphenyl)-coumarin having high affinity and 6-hydroxy-3-(3-hydroxyphenyl)-coumarin with high intrinsic clearance.