![]() |
|
|
BE Daikh, RM Laethem and DR Koop
Department of Pharmacology, Oregon Health Sciences University, Portland.
In the present study, we determined the stereoselective epoxidation of arachidonic acid by cytochrome P-450 (P-450) 2CAA and P-450 2C2, two arachidonic acid epoxygenases found in rabbit renal cortex, by chiral normal-phase high-performance liquid chromatography (HPLC)-analysis. Purified P-450 2CAA reconstituted with P-450 oxidoreductase, lipid and cytochrome b5 or microsomes isolated from COS-1 cells expressing P-450 2C2 were incubated in the presence of [1-14C]arachidonic acid. The epoxide metabolites 14,15- and 11,12-epoxyeicosatrienoic acids (EETs) were purified by reverse-phase HPLC and derivatized to methyl (14,15- EET) and pentafluorobenzyl (11,12-EET) esters. Enantiomers of 14,15-EET- methyl ester and 11,12-EET-pentafluorobenzyl ester were resolved on Chiralcel OB and OD columns, respectively, with a mobile phase of 0.15% 2-propanol in n-hexane. P-450 2CAA and P-450 2C2 produce 11,12- and 14,15-EETs in distinct ratios but are equally stereoselective at the 11,12-position. P-450 2CAA produced 11(S), 12(R)-EET with 63% stereoselectivity, and P-450 2C2 produced the same enantiomer with 61% stereoselectivity. Both enzymes are also stereoselective at the 14,15- position, preferentially producing the 14(R), 15(S)-EET. P-450 2CAA produces this enantiomer with 72% selectivity, and P-450 2C2 produces it with 62% selectivity. The results of this study indicate that P-450 2CAA and P-450 2C2 are not only regioselective but also exhibit a high degree of stereoselectivity.
This article has been cited by other articles:
![]() |
H. Jiang, J. C. McGiff, J. Quilley, D. Sacerdoti, L. M. Reddy, J. R. Falck, F. Zhang, K. M. Lerea, and P. Y-K Wong Identification of 5,6-trans-Epoxyeicosatrienoic Acid in the Phospholipids of Red Blood Cells J. Biol. Chem., August 27, 2004; 279(35): 36412 - 36418. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. J. Roman P-450 Metabolites of Arachidonic Acid in the Control of Cardiovascular Function Physiol Rev, January 1, 2002; 82(1): 131 - 185. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. H. Capdevila, J. R. Falck, and R. C. Harris Cytochrome P450 and arachidonic acid bioactivation: molecular and functional properties of the arachidonate monooxygenase J. Lipid Res., February 1, 2000; 41(2): 163 - 181. [Abstract] [Full Text] |
||||