Cytochrome P450 catalyzed metabolism of 1,2-dibromoethane in liver microsomes of differentially induced rats
| Autor: | P.J. van Bladeren, J.H.T.M. Ploemen, Nico P. E. Vermeulen, Jan N. M. Commandeur, L.W. Wormhoudt, B. van Ommen |
|---|---|
| Přispěvatelé: | Molecular and Computational Toxicology, Medicinal chemistry |
| Jazyk: | angličtina |
| Rok vydání: | 1996 |
| Předmět: |
Male
Adenosine Acetaldehyde beta-Naphthoflavone Toxicology chemistry.chemical_compound Cytochrome P-450 Enzyme System SDG 3 - Good Health and Well-being Animals Hypnotics and Sedatives Enzyme kinetics Enzyme Inhibitors Rats Wistar Derivatization Chromatography High Pressure Liquid Benzoflavones Chromatography biology Molecular Structure Temperature Cytochrome P450 General Medicine Glutathione Metabolism Hydrogen-Ion Concentration Rats Ethylene Dibromide Isoenzymes Kinetics Biochemistry chemistry Enzyme Induction Phenobarbital biology.protein Microsome Microsomes Liver 1 2-Dibromoethane Pyrazoles NADP |
| Zdroj: | Chemico-Biological Interactions, 99, 41-53. Elsevier Ireland Ltd Wormhoudt, L W, Ploemen, J P H T M, Commandeur, J N M, van Ommen, B, van Bladeren, P J & Vermeulen, N P E 1996, ' Cytochrome P450 catalyzed metabolism of 1,2-dibromoethane in liver microsomes of differentially induced rats. ', Chemico-Biological Interactions, vol. 99, pp. 41-53 . https://doi.org/10.1016/0009-2797(95)03659-8 |
| ISSN: | 0009-2797 |
| DOI: | 10.1016/0009-2797(95)03659-8 |
| Popis: | The cytochrome P450 (P450) catalyzed oxidation of 1,2-dibromoethane (1,2-DBE) to 2-bromoacetaldehyde (2-BA) was measured in liver microsomes of both control and differentially induced rats. 2-BA formation was quantified by derivatization of 2-BA with adenosine (ADO), resulting in the formation of the highly fluorescent 1,N6-ethenoadenosine (epsilon-ADO), which was measured by HPLC. After microsomal incubation with 1,2DBE in the presence of ADO and removal of proteins by denaturation and centrifugation, derivatization by heating 4 h at 65 degrees C appeared necessary to ensure efficient formation of epsilon-ADO. Using this optimized derivatization method to quantitate 2-BA formation, the enzyme kinetics of the P450 catalyzed oxidation of 1,2-DBE to 2-BA were measured in liver microsomes prepared from untreated rats and rats pretreated with phenobarbital (PB), beta-naphtoflavone (beta NF) and pyrazole (PYR). P450 isoenzymes in PYR- and beta NF-induced microsomes showed linear enzyme kinetics while P450 isoenzymes in control and PB-induced microsomes showed non-linear enzyme kinetics. The apparent Vmax- and Km- values for the metabolism of 1,2-DBE to 2-BA were 2.5 nmol/min/mg protein and 144 microns for P450 isoenzymes in PYR-induced microsomes and 773 pmol/min/mg protein and 3.3 mM for P450 isoenzymes in beta NF-induced microsomes, respectively. Due to the non-linear enzyme kinetics of the P450 catalyzed oxidation of 1,2-DBE to 2-BA using control and PB-induced microsomes, no proper Vmax- and Km- values could be calculated. However, from Michaelis-Menten plots it was clear that the affinity of P450 isoenzymes for 1,2-DBE in control and PB-induced microsomes was in the same range when compared to beta NF-induced microsomes and thus much lower than the PYR-induced microsomes. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect