Novel glutathione conjugates formed from epoxyeicosatrienoic acids (EETs).
The catalysis of glutathione (GSH) conjugation to epoxyeicosatrienoic acids (EETs) by various purified isozymes of glutathione S-transferase was studied. A GSH conjugate of 14,15-EET was isolated by HPLC and TLC; this metabolite contained one molecule of EET and one molecule of GSH. Fast atom bombardment mass spectrometry of the isolated metabolite confirmed the structure as a GSH conjugate of 14,15-EET. Studies designed to determine the isozyme specificity of this reaction demonstrated that two isozymes, 3-3, and 5-5, efficiently catalyzed this conjugation reaction. The Km values for 14,15-EET were approximately 10 microM and the Vmax values ranged from 25 to 60 nmol conjugate formed min-1 mg-1 purified transferase 3-3 and 5-5. The 5,6-, 8,9-, and 11,12-EETs were also substrates for the reaction, albeit at lower rates. These results demonstrate that the EETs can serve as substrates for the cytosolic glutathione S-transferases.
D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D008297:Male; D013058:Mass Spectrometry; D051381:Rats; D011919:Rats, Inbred Strains; D013379:Substrate Specificity
D005231:Fatty Acids, Unsaturated; D007527:Isoenzymes; C040776:5,6-epoxy-8,11,14-eicosatrienoic acid; D005982:Glutathione Transferase; D015126:8,11,14-Eicosatrienoic Acid; D005978:Glutathione