Metabolism of estradiol by uterine peroxidase: nature of the water-soluble products.

The nature of the water-soluble products formed by incubating labelled estradiol with uterine peroxidase in the presence of H2O2 and tyrosine was examined by two-dimensional thin-layer chromatography and high voltage electrophoresis. It was shown that the steroid and amino acid were associated in a 1:2 or 1:3 ratio and evidence was provided by 3H-exchange for the interaction of tyrosine with ring A of estradiol at C-2 and C-4. The possible role of estrogen-induced peroxidase in the uterus in vivo is discussed.