Purification of a 17β-Hydroxysteroid Dehydrogenase of Human Placenta and Studies on Its Transhydrogenase Function

Abstract

This paper describes methods for the extensive purification of a soluble 17@-hydroxysteroid dehydrogenasel of human placenta. This single enzyme appears to be responsible for the entire 17/3estradiol-mediated transfer of hydrogen between pyridine nucleotides in soluble extracts of this tissue. Experiments which were reported in 1958 (2, 3) showed that soluble enzyme preparations derived from human placenta promoted a reversible transhydrogenation between pyridine nucleotides in the presence of low concentrations of 17&hydroxyst,eroids or 17-ketosteroids, notably 17/I-estradiol or estrone. These enzyme preparations also contained an active 17/3-hydroxysteroid dehydrogenase which interconverts 17@estradiol and estrone, and reacts with diphosphopyridine nucleotide (DPN) or triphosphopyridine nucleotide (TPN) (8, 9, 11). We suggested (2, 3) that the 17/3-estradiol-mediated transfer of hydro