J. Biol. Chem., Vol. 260, Issue 21, 11520-11523, Sep, 1985
Putative inhibitor of cyclic AMP efflux: chromatography, amino acid composition, and identification as a prostaglandin A1-glutathione adduct
LE Heasley, MJ Watson and LL Brunton
Avian red cells rapidly and extensively metabolize prostaglandin A1 (PGA1)
to a polar form that extracts into 80% ethanol and is quantitatively
desalted and recovered over a Waters C18 Sep-Pak. This material
co-chromatographs with synthetic PGA1-GSH and with the human red cell PGA1
metabolite on cellulose and silica gel thin layer plates and on normal
phase high performance liquid chromatography. Quantitation of the amino
acid composition by [35S]cysteine incorporation and by fluorometric amino
acid analysis of the material eluting from high performance liquid
chromatography indicates the presence of PGA1, cysteine, glutamate, and
glycine in equimolar ratios. Base sensitivity of the metabolite indicates
that it exists largely (80%) in the 9-hydroxyl form. We conclude that the
polar metabolite of PGA1 that acts intracellularly to inhibit cyclic AMP
efflux by avian red cells is a glutathione conjugate of PGA1.