Abstract
CYP2S1 is a recently described dioxin-inducible cytochrome P450. We previously demonstrated that human CYP2S1 oxidizes a number of carcinogens but only via the peroxide shunt. In this article, we investigated whether human CYP2S1 can metabolize cyclooxygenase- and lipoxygenase-derived lipid peroxides in a NADPH-independent fashion. Human CYP2S1 metabolizes prostaglandin G2 (PGG2) (Km = 0.267 ± 0.072 μM) into several products including 12S-hydroxy-5Z,8E,10E-heptadecatrienoic acid (12-HHT). It also metabolizes prostaglandin H2 (PGH2) (Km = 11.7 ± 2.8 μM) into malondialdehyde, 12-HHT, and thromboxane A2 (TXA2). The turnover to 12-HHT by human CYP2S1 (1.59 ± 0.04 min−1) is 40-fold higher than that of TXA2 (0.04 min−1). In addition to PGG2 and PGH2 metabolism, human CYP2S1 efficiently metabolizes the hydroperoxyeicosatetraenoic acids (5S-, 12S-, and 15S-) and 13S-hydroperoxyoctadecadienoic acid into 5-oxo-eicosatetraenoic acid (turnover = 16.7 ± 0.3 min−1), 12-oxo-eicosatetraenoic acid 1 (11.5 ± 0.9 min−1), 15-oxo-eicosatetraenoic acid (16.9 ± 0.8 min−1), and 13-octadecadienoic acid (20.2 ± 0.9 min−1), respectively. Other cytochromes P450 such as CYP1A1, 1A2, 1B1, and 3A4 underwent similar conversions but at slower rates. The fatty acid hydroperoxides were also converted by human CYP2S1 to several epoxyalcohols. Our data indicate that fatty acid endoperoxides and hydroperoxides represent endogenous substrates of CYP2S1 and suggest that the enzyme CYP2S1 may play an important role in the inflammatory process because some of the products that CYP2S1 produces play important roles in inflammation.
Footnotes
This work was supported by the National Institutes of Health National Institute of Environmental Health Sciences [Grant R01-ES015384]; P.B. was supported by a predoctoral fellowship from the National Institutes of Health National Institute of Environmental Health Sciences [Training Grant T32-ES015457].
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
doi:10.1124/dmd.110.035121.
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The online version of this article (available at http://dmd.aspetjournals.org) contains supplemental material.-
ABBREVIATIONS:
- HETE
- hydroxyeicosatetraenoic acid
- HpETE
- hydroperoxyeicosatetraenoic acid
- P450
- cytochrome P450
- MDA
- malondialdehyde
- TXA2
- thromboxane A2
- PGH2
- 9α,11α-epidioxy-15S-hydroxy-prosta-5Z,13E-dien-1-oic acid
- PGG2
- 9α,11α-epidioxy-15S-hydroperoxy-prosta-5Z,13E-dien-1-oic acid
- PGE2
- 9-oxo-11α,15S-dihydroxy-prosta-5Z,13E-dien-1-oic acid
- PGD2
- 9α,15S-dihydroxy-11-oxo-prosta-5Z,13E-dien-1-oic acid
- TXB2
- 9α,11,15S-trihydroxythromba-5Z,13E-dien-1-oic acid
- 15(S)-HETE-d8
- 15(S)-hydroxy-5Z,8Z,11Z,13E-eicosatetraenoic-5,6,8,9,11,12,14,15-d8 acid
- 13(S)-HODE-d4
- 13(S)-hydroxy-9Z,11E-octadecadienoic-9,10,12,13-d4 acid
- 5-HpETE
- 5S-hydroperoxy-6E,8Z,11Z,14Z-eicosatetraenoic acid
- 12-HpETE
- 12S-hydroperoxy-5Z,8Z,10E,14Z-eicosatetraenoic acid
- 15-HpETE
- 15S-hydroperoxy-5Z,8Z,10E,14Z-eicosatetraenoic acid
- 13-HpEODE
- 13S-hydroperoxy-9Z,11E-octadecadienoic acid
- 5-oxoETE
- 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid
- 12-oxoETE
- 12-oxo-5Z,8Z,10E,14Z-eicosatetraenoic acid
- 15-oxoETE
- 15-oxo-5Z,8Z,10E,14Z-eicosatetraenoic acid
- 12-oxoODE
- 13-oxo-9Z,11E-octadecadienoic acid
- 5-HETE
- 5S-hydroxy-6E,8Z,11Z,14Z-eicosatetraenoic acid
- 12-HETE
- 12S-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid
- 15-HETE
- 15S-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid
- 13-HODE
- 13S-hydroxy-9Z,11E-octadecadienoic acid
- 12-HHT
- 12S-hydroxy-5Z,8E,10E-heptadecatrienoic acid
- HPLC
- high-performance liquid chromatography
- Kpi
- potassium phosphate buffer
- LC
- liquid chromatography
- ESI
- electrospray ionization
- MS/MS
- tandem mass spectrometry
- SPE
- solid-phase extraction
- oxoETE
- oxo-eicosatetraenoic acid
- oxoODE
- oxo-octadecadienoic acid
- HpODE
- hydroperoxy-octadecadienoic acid
- MRM
- multiple reaction monitoring
- SIM
- selected ion monitoring
- COX
- cyclooxygenase
- 15-oxo-PGG2
- 9α,11α-epidioxy-15S-oxo-prosta-5Z,13E-dien-1-oic acid
- 12-oxo-HT
- 12-oxo-5Z,8E,10E-heptadecatrienoic acid
- AQ4N
- 1,4-bis{[2-(dimethylamino-N-oxide)ethyl]amino}-5,8-dihydroxyanthracene-9,10-dione.
- Received June 23, 2010.
- Accepted November 4, 2010.
- Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics
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