Abstract
5(6)-Epoxy-8,11,14-eicosatrienoic acid was incubated with microsomes or ram seminal vesicles in the presence of glutathione (1 mM) for 2 min at 37°C. Following extractive isolation on octadecasilane silica, the products were purified on straight-phase HPLC and separated into three major polar metabolites, which all showed maximal ultraviolet absorbance at 278 nm after treatment with alkali. The least-polar of the three metabolites was identified by capillary column gas chromatography-mass spectrometry as 5(6)-epoxyprostaglandin E 1 and the structure was confirmed by comparison with authentic material. The most-polar metabolite was identified as 5,6-dihydroxyprostaglandin E 1, while the metabolite of medium polarity was identified as its 85-lactone. When glutathione was omitted, 5-hydroxyprostaglandin I 1α and 5-hydroxyprostaglandin I 1β were previously identified as the two major metabolites. These results indicate that the postulated epoxyprostaglandin endoperoxide intermediates, 5(6)-epoxyprostaglandin G 1 and 5(6)-epoxyprostaglandin H 1, might be substrates for the endoperoxide E isomerase enzyme, since this enzyme requires glutathione as a cofactor.
Published Version
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