Figure 1.

Peroxynitrite stimulation of AA metabolism by PGH synthase-1. Purified ram seminal vesicle PGH synthase-1 (22 nM) was incubated at 37°C with 8 units bovine erythrocyte GSH-Px, GSH, and 10 μg catalase in 0.1 M NaPO₄ (pH 8.0) containing 500 μM phenol (200 μl reaction volume). Following addition of 50 μM [1-¹⁴C]AA, peroxynitrite was added and reactions were terminated with ethyl ether/methanol/1 M citric acid (pH 4.0) (30:4:1) after 2 min. Radiolabeled arachidonate metabolites were separated by thin-layer chromatography and quantitated using a radioactivity scanner. Control PGH synthase-1 activity in the absence of GSH-Px was 870 and 559 pmol product/pmol PGH synthase-1 at 0.2 and 1 mM GSH, respectively. □, 0.2 mM GSH; ▪, 1 mM GSH.