Isolation and sequencing of a complementary deoxyribonucleic acid clone encoding human placental 173-estradiol dehydrogenase: Identification of the putative cofactor binding site

17β-Estradiol dehydrogenase (EC 1.1.1.62) catalyzes the interconversion of estradiol and estrone in human term placenta. We have raised a specific polyclonal antibody to this abundant placental enzyme to study its role in late pregnancy events and its molecular biologic characteristics. In this work the 17β-estradiol dehydrogenase antibody was used to isolate and sequence a complementary deoxyribonucleic acid clone encoding about 98% of the amino acid sequence of the 17β-estradiol dehydrogenase molecule. This sequence verifies previous sequence data on the molecule's steroid binding site and also localizes a putative nicotinamide adenine dinucleotide binding region similar to that of many other pyridine nucleotide-dependent dehydrogenases. Isolation of the complementary deoxyribonucleic acid for 17β-estradiol dehydrogenase expands our knowledge of the structure-function relationships of the enzyme and is a major step in our understanding of its biologic function in pregnancy.