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Novel glutathione conjugates formed from epoxyeicosatrienoic acids (EETs)

1985; Elsevier BV; Volume: 242; Issue: 1 Linguagem: Inglês

10.1016/0003-9861(85)90496-5

1096-0384

M E Spearman, Russell A. Prough, Ronald W. Estabrook, John R. Falck, Sukumar Manna, Kenneth C. Leibman, Robert C. Murphy, Jorge H. Capdevila,

Adenosine and Purinergic Signaling

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 μm 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.