title: Inhibitory and non-inhibitory monoclonal antibodies to human cytochrome P450 3A3/4.
abstract: Cytochromes P450 3A3/4 are inordinately important P450 enzymes catalyzing the metabolism of a large variety of clinically useful drugs, steroids, and carcinogens. Two monoclonal antibodies, MAb 3-29-9 and MAb 275-1-2, were prepared to human P450 3A4 from mice immunized with baculovirus-expressed human P450 3A4. MAb 3-29-9 was a powerful inhibitor of the enzymatic activity of P450 3A3/4/5. MAb 3-29-9 inhibited the P450 3A3, 3A4, and 3A5 catalyzed metabolism of substrates of divergent molecular weights, e.g., p-nitroanisole, phenanthrene, diazepam, testosterone, taxol, and cyclosporin. However, MAb 3-29-9 did not give a western blot with P450 3A3 or 3A4. MAb 275-1-2 was non-inhibitory but yielded a strong western blot with P450 3A3 and 3A4 but not with 3A5, and thus distinguished between 3A3/4 and 3A5. The two MAbs did not cross-react with human 2E1, 1A2, 2B6, 2C8, and 2C9; rat 2A1, 3A1/2, 4A1, 4A3, and 2B1; and mouse 1A1 and 1A2. MAb 3-29-9 has been used successfully to measure the quantitative contribution of P450 3A3 and 3A4 to the metabolism of the above-designated substrates in human adult liver. MAb 3-29-9 and MAb 275-1-2 are precise and sensitive reagents for P450 3A studies.
authors.affiliation: Laboratory of Molecular Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: H V
authors.initials: HV
authors.lastname: Gelboin
authors.forename: K W
authors.initials: KW
authors.lastname: Krausz
authors.forename: I
authors.initials: I
authors.lastname: Goldfarb
authors.forename: J T
authors.initials: JT
authors.lastname: Buters
authors.forename: S K
authors.initials: SK
authors.lastname: Yang
authors.forename: F J
authors.initials: FJ
authors.lastname: Gonzalez
authors.forename: K R
authors.initials: KR
authors.lastname: Korzekwa
authors.forename: M
authors.initials: M
authors.lastname: Shou
mesh_terms: D000840:Anisoles / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D015153:Blotting, Western; D003429:Cross Reactions; D016572:Cyclosporine / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology / Q000378:metabolism; D003975:Diazepam / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D007202:Indicators and Reagents; D008099:Liver / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000378:metabolism; D017239:Paclitaxel / Q000378:metabolism; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors; D013739:Testosterone / Q000378:metabolism
chemical_list: D000840:Anisoles; D000911:Antibodies, Monoclonal; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D007202:Indicators and Reagents; D011994:Recombinant Proteins; D013739:Testosterone; D016572:Cyclosporine; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C005306:4-nitroanisole; D017239:Paclitaxel; D003975:Diazepam