Resolution of prostaglandin endoperoxide synthase and thromboxane synthase of human platelets.

Thromboxane synthase was localized to the microsomes of human platelets. The enzyme was insensitive to sulfhydryl reagents and thiols but was inhibited by 12L-hydroperoxy-5, 8, 10, 14-eicosatetraenoic acid (concentration for 50% inhibition = 0.1 mM). Treatment of microsomes with Triton X-100 solubilized the enzymes that catalyze the conversion of arachidonic acid to thromboxane B2. The solubilized material was resolved by DEAE-cellulose chromatography into two components, one converting arachidonic acid to prostaglandins G2 and H2 and the other converting prostaglandin H2 to thromboxane B2.