Roles of Human CYP2A6 and Monkey CYP2A24 and 2A26 Cytochrome P450 Enzymes in the Oxidation of 2,5,2',5'-Tetrachlorobiphenyl.
2,5,2',5'-Tetrachlorobiphenyl (TCB) induced type I binding spectra with cytochrome P450 (P450) 2A6 and 2A13, with Ksvalues of 9.4 and 0.51 µM, respectively. However, CYP2A6 oxidized 2,5,2',5'-TCB to form 4-hydroxylated products at a much higher rate (∼1.0 minute-1) than CYP2A13 (∼0.02 minute-1) based on analysis by liquid chromatography-tandem mass spectrometry. Formation of 4-hydroxy-2,5,2',5'-TCB by CYP2A6 was greater than that of 3-hydroxy-2,5,2',5'-TCB and three other hydroxylated products. Several human P450 enzymes, including CYP1A1, 1A2, 1B1, 2B6, 2D6, 2E1, 2C9, and 3A4, did not show any detectable activities in oxidizing 2,5,2',5'-TCB. Cynomolgus monkey CYP2A24, which shows 95% amino acid identity to human CYP2A6, catalyzed 4-hydroxylation of 2,5,2',5'-TCB at a higher rate (∼0.3 minute-1) than CYP2A26 (93% identity to CYP2A6, ∼0.13 minute-1) and CYP2A23 (94% identity to CYP2A13, ∼0.008 minute-1). None of these human and monkey CYP2A enzymes were catalytically active in oxidizing other TCB congeners, such as 2,4,3',4'-, 3,4,3',4'-, and 3,5,3',5'-TCB. Molecular docking analysis suggested that there are different orientations of interaction of 2,5,2',5'-TCB with the active sites (over the heme) of human and monkey CYP2A enzymes, and that ligand interaction energies (U values) of bound protein-ligand complexes show structural relationships of interaction of TCBs and other ligands with active sites of CYP2A enzymes. Catalytic differences in human and monkey CYP2A enzymes in the oxidation of 2,5,2',5'-TCB are suggested to be due to amino acid changes at substrate recognition sites, i.e., V110L, I209S, I300F, V365M, S369G, and R372H, based on the comparison of primary sequences.
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.) t.shimada@vet.osakafu-u.ac.jp.
Tsutomu
T
Shimada
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
Kensaku
K
Kakimoto
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
Shigeo
S
Takenaka
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
Nobuyuki
N
Koga
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
Shotaro
S
Uehara
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
Norie
N
Murayama
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
Hiroshi
0000-0002-1068-4261
H
Yamazaki
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
Donghak
D
Kim
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
F Peter
FP
Guengerich
Laboratory of Cellular and Molecular Biology, Osaka Prefecture University, Izumisano, Osaka, Japan (T.S., S.T., M.K.); Osaka Prefectural Institute of Public Health, Higashinari-ku, Osaka, Japan (K.K.); Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan (N.K.); Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Machida, Tokyo, Japan (S.U., N.M., H.Y.); Department of Biological Sciences, Konkuk University, Seoul, South Korea (D.K.); and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee (F.P.G.).
Masayuki
M
Komori
D000818:Animals; D002384:Catalysis; D020134:Catalytic Domain / Q000502:physiology; D065637:Cytochrome P-450 CYP2A6 / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D000882:Haplorhini; D006801:Humans; D008024:Ligands; D062105:Molecular Docking Simulation / Q000379:methods; D010084:Oxidation-Reduction; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology
D008024:Ligands; C009407:2,5,2',5'-tetrachlorobiphenyl; D003577:Cytochrome P-450 Enzyme System; D011078:Polychlorinated Biphenyls; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6