Estradiol-17/? dehydrogenase placental

We have studied the reaction of the potential afiSnity label, 3-bromo-acetoxyestrone, with human placental estradiol dehydrogenase and have found that it satisfies the first four criteria for an afiSnity label. Furthermore, the 17-keto group of this compound offers an opportunity to determine whether, after reaction with the enzyme, the covalently bound steroid is suitably positioned to serve as a substrate in the dehydrogenase reaction. We provide evidence that such is indeed the case. 

Langer, L. j., and L. L. Engel Human placental estradiol-17j dehydrogenase. I. Concentration, characterization and assay. J. biol. Chem. 233, 583 (1958). 

The first clear-cut effect of an estri enic hormone added in vitro to an enzyme system was reported by Hagerman and Villee (1953) and Villee and Hagerman (1953), who showed that the addition of estradiol-17/3 to slices of human endometrium or placenta incubated in vitro produced an increased rate of oxidative metabolism. In placental homogenates the locus of action of estradiol was considered to be a diphosphopyridine nucleotide-linked isocitric dehydrogenase present in the soluble fraction (Villee and Gordon, 1955). Triphosphopyridine nucleotide did not replace diphosphopyridine nucleotide (Villee, 1955), and a divalent metal cation is required for full... 

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