Inhibitory and non-inhibitory monoclonal antibodies to human cytochrome P450 3A3/4

• Published in: Biochemical pharmacology 1995-11, Vol.50 (11), p.1841-1850
• Main Authors: Gelboin, Harry V., Krausz, Kristopher W., Goldfarb, Inna, Buters, Jeroen T.M., Yang, Shen K., Gonzalez, Frank J., Korzekwa, Kenneth R., Shou, Magang
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Anisoles - metabolism; Antibodies, Monoclonal - immunology; Antibodies, Monoclonal - pharmacology; Biological and medical sciences; Blotting, Western; Cross Reactions; cyclosporin; Cyclosporine - metabolism; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System - immunology; Cytochrome P-450 Enzyme System - metabolism; diazepam; Diazepam - metabolism; Enzyme Inhibitors - pharmacology; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; human P450 3A4; Humans; Indicators and Reagents; inhibitory monoclonal antibodies; Liver - enzymology; Mixed Function Oxygenases - antagonists & inhibitors; Mixed Function Oxygenases - immunology; Mixed Function Oxygenases - metabolism; Oxidoreductases; p-nitroanisole; Paclitaxel - metabolism; phenanthrene; Recombinant Proteins - antagonists & inhibitors; taxol; testosterone; Testosterone - metabolism; western blot
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/0006-2952(95)02077-2

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.