Human Placental 17β-Estradiol Dehydrogenase

Abstract

Abstract Human placental 17β-estradiol dehydrogenase, homogeneous by polyacrylamide disc gel electrophoresis, has been prepared in good yield by a four-step procedure. The method consists of ammonium sulfate fractionation of placental homogenates, followed by chromatography on hydroxylapatite, DEAE-cellulose, and, finally, hydroxylapatite. The product has a specific activity of 10.5 µmoles of 17β-estradiol min-1 mg-1 in the presence of DPN and 8.1 µmoles of 17β-estradiol min-1 mg-1 in the presence of TPN and a molecular weight of 48,000 as determined by mobility on sodium dodecyl sulfate disc gel electrophoresis. The kinetic constants for both the DPN- and TPN-linked activities were determined.