Capillary electrophoresis of cytochrome P-450 epoxygenase metabolites of arachidonic acid. 2. Resolution of stereoisomers.
Each of the four regioisomers of epoxyeicosatrienoic acids (EETs) is a candidate for being an endothelial-dependent hyperpolarizing factor (EDHF). One regioisomer, 14,15-EET, stereospecifically blocks cyclooxygenases from converting arachidonic acid to prostaglandins and stereospecifically binds to cellular receptors. Both stereospecific actions emphasize the need to establish the tissue availability of the 14,15-EET enantiomers. The present work describes a method to quantitate picogram amounts of 14,15-EET enantiomers by capillary electrophoresis. The 14,15-EET enantiomers were baseline resolved (R = 1.3) using unsubstituted beta-cyclodextrin and 32% acetonitrile (v/v). When absorption at 194 nm was monitored using a photodiode array detector, 8 and 1 pg of underivatized 14,15-EET were readily quantitated and detected, respectively. Capillary electrophoresis accurately assessed chiral excesses up to 97:3 for either 14,15-EET enantiomer. Moreover, capillary electrophoresis with a photodiode array detector was sufficiently sensitive to detect and measure 14,15-EET enantiomers from murine liver. Thus, unlike chiral-phase high-performance liquid chromatography, capillary electrophoresis can be used to directly assess the chirality of trace amounts of underivatized eicosanoids.
Vandernoot
Victoria A
VA
Department of Chemical & Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, USA.
VanRollins
Mike
M
D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002138:Calibration; D003505:Cyclodextrins; D000090762:Cytochrome P-450 CYP2J2; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D019075:Electrophoresis, Capillary; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D010105:Oxygenases / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
D003505:Cyclodextrins; D016718:Arachidonic Acid; C046782:14,15-epoxy-5,8,11-eicosatrienoic acid; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; D000090762:Cytochrome P-450 CYP2J2; D015126:8,11,14-Eicosatrienoic Acid