Cytochrome P450 4A isoform inhibitory profile of N-hydroxy-N'-(4-butyl-2-methylphenyl)-formamidine (HET0016), a selective inhibitor of 20-HETE synthesis.
We examined the effect of N-hydroxy-N'-(4-butyl-2-methylphenyl)-formamidine) (HET0016), an inhibitor of 20-hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE) synthesis on the omega-hydroxylation and epoxidation of arachidonic acid (AA) catalyzed by recombinant cytochrome P450 4A1 (CYP4A1), CYP4A2 and CYP4A3, and characterized the enzyme inhibitory profile of HET0016. The IC50 values of HET0016 for recombinant CYP4A1-, CYP4A2- and CYP4A3-catalyzed 20-HETE synthesis averaged 17.7 nM, 12.1 nM and 20.6 nM, respectively. The IC50 value for production of 11,12-epoxy-5,8,14-eicosatrienoic acid (11,12-EET) by CYP4A2 and 4A3 averaged 12.7 nM and 22.0 nM, respectively. The IC50 value for CYP2C11 activity was 611 nM which was much greater than that for CYP4As. The initial velocity study showed the Ki value of HET0016 for CYP4A1 was 19.5 nM and a plot of Vmax versus amount of recombinant CYP4A1 added shows HET0016 is an irreversible non-competitive inhibitor. These results indicate that HET0016 is a selective, non-competitive and irreversible inhibitor of CYP4A.
Seki
Takayuki
T
Medicinal Pharmacology Laboratory, Medicinal Research Laboratories, Taisho Pharmaceutical Co., Ltd., Saitama, Japan. takayuki.seki@po.rd.taisho.co.jp
Wang
Mong-Heng
MH
Miyata
Noriyuki
N
Laniado-Schwartzman
Michal
M
D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D000578:Amidines / Q000494:pharmacology*; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D042926:Cytochrome P-450 CYP4A / Q000037:antagonists & inhibitors*; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System; D000072470:Cytochrome P450 Family 4; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006893:Hydroxyeicosatetraenoic Acids / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D007700:Kinetics; D010084:Oxidation-Reduction; D051381:Rats
D000578:Amidines; C465387:Cyp4a1protein, rat; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; C000708209:HET0016; D006893:Hydroxyeicosatetraenoic Acids; D016718:Arachidonic Acid; C046783:11,12-epoxy-5,8,14-eicosatrienoic acid; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; D003577:Cytochrome P-450 Enzyme System; D000072470:Cytochrome P450 Family 4; C465389:Cyp4a3 protein, rat; D042926:Cytochrome P-450 CYP4A; C465388:cytochrome P-450 CYP4A2 (rat); D015126:8,11,14-Eicosatrienoic Acid