Research article - Peer-reviewed, 2011
Para-nitrophenol hydroxylation by fish liver microsomes: kinetics and effect of selective cytochrome P450 inhibitors
Zamaratskaia, Galia; Zlabek, VladimirAbstract
The study investigated the kinetics of p-nitrophenol hydroxylase (PNPH) in hepatic microsomes obtained from Atlantic salmon (Salmo salar). The selective inhibitors for some major mammalian cytochrome P450 (CYP450) were used to investigate the potential inhibitory effect on enzymes involved in p-nitrophenol hydroxylation. The following inhibitors were used: alpha-naphtoflavone (CYP1A), ellipticine (CYP1A1), furafylline (CYP1A2), 8-methoxypsoralen (8MOP, CYP2A6), 4-methylpyrazole (4MP, CYP2A6/2E1), diallyl sulfide (DAS, CYP2E1), and ketoconazole (CYP3A4). Additionally, the natural steroids 17-beta-oestraiol (E2) and testosterone were investigated as potential inhibitors of PNPH activity. It was found that formation of 4-nitrocatechol from p-nitrophenol followed monophasic kinetics with K (m) = 0.17 +/- A 0.03 mM and V (max) = 21.8 +/- A 1.05 pmol/min/mg. PNPH activity was competitively inhibited by diallyle sulfide with the K (i) value of 285.1 +/- A 94.2 mu M mu M and uncompetitively by ellipticine with K (i) value of 65.7 +/- A 7.8 mu M. Moreover, E2 showed an ability to reduce PNPH activity through the mechanism-based inhibition mode. Our results suggest that hepatic microsomes from Atlantic salmon possess CYP2E1-like activity. However, specific isoform-mediated PNPH activity should be identified.Keywords
Atlantic salmon; Hepatic microsomes; P-nitrophenol; Diallyl sulfide; EllipticinePublished in
Fish Physiology and Biochemistry2011, volume: 37, number: 4, pages: 969-976
Publisher: SPRINGER
Authors' information
Swedish University of Agricultural Sciences, Department of Food Science
Zlabek, Vladimir
Swedish University of Agricultural Sciences, Department of Food Science
UKÄ Subject classification
Physiology
Fish and Aquacultural Science
Biochemistry and Molecular Biology
Publication Identifiers
DOI: https://doi.org/10.1007/s10695-011-9494-z
URI (permanent link to this page)
https://res.slu.se/id/publ/46244