An inhibitor of prostaglandin biosynthesis from human decidua: partial purification and properties

An inhibitor of prostaglandin synthetase which catalyzes the conversion of arachidonic acid into prostaglandin E2 was partially purified from the 105,000 x g supernatant fraction of the human decidual cell homogenate. By means of ammonium sulfate fractionation, Mono Q ion-exchange chromatography, and gel filtration chromatography, the inhibitor was purified about 15-fold, giving a preparation with a molecular weight of 55-60 KDa. The 50% inhibitory concentration of the purified substance was approximately 0.2 mg/ml. The inhibitor may play a role in suppression of prostaglandin production by decidua in early pregnancy.