title: Expression and characterization of human cytochrome P450 4F11: Putative role in the metabolism of therapeutic drugs and eicosanoids.
abstract: We previously reported the cDNA cloning of a new CYP4F isoform, CYP4F11. In the present study, we have expressed CYP4F11 in Saccharomyces cerevisiae and examined its catalytic properties towards endogenous eicosanoids as well as some clinically relevant drugs. CYP4F3A, also known as a leukotriene B4 omega-hydroxylase, was expressed in parallel for comparative purposes. Our results show that CYP4F11 has a very different substrate profile than CYP4F3A. CYP4F3A metabolized leukotriene B4, lipoxins A4 and B4, and hydroxyeicosatetraenoic acids (HETEs) much more efficiently than CYP4F11. On the other hand, CYP4F11 was a better catalyst than CYP4F3A for many drugs such as erythromycin, benzphetamine, ethylmorphine, chlorpromazine, and imipramine. Erythromycin was the most efficient substrate for CYP4F11, with a Km of 125 microM and Vmax of 830 pmol min(-1) nmol(-1) P450. Structural homology modeling of the two proteins revealed some interesting differences in the substrate access channel including substrate recognition site 2 (SRS2). The model of CYP4F11 presents a more open access channel that may explain the ability to metabolize large molecules like erythromycin. Also, some wide variations in residue size, charge, and hydrophobicity in the FG loop region may contribute to differences in substrate specificity and activity between CYP4F3A and CYP4F11.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77030, USA.
authors.forename: Auinash
authors.initials: A
authors.lastname: Kalsotra
authors.forename: Cheri M
authors.initials: CM
authors.lastname: Turman
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kikuta
authors.forename: Henry W
authors.initials: HW
authors.lastname: Strobel
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D000072470:Cytochrome P450 Family 4; D015777:Eicosanoids / Q000378:metabolism*; D004917:Erythromycin / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics / Q000502:physiology; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D015777:Eicosanoids; D007527:Isoenzymes; D004364:Pharmaceutical Preparations; D004917:Erythromycin; D003577:Cytochrome P-450 Enzyme System; D000072470:Cytochrome P450 Family 4; C492722:CYP4F11 protein, human; C465349:CYP4F3 protein, human