Effect of phenols on the oxidation of estradiol by uterine peroxidase.

The effect of various phenols on the conversion of [4 -14C]estradiol to water-soluble products by estrogen-induced uterine peroxidase (EC 1.11.1.7) has been investigated. Evidence was provided that those phenols which enhanced the oxidation of estradiol exerted their effect by activating peroxidase or protecting the enzyme from inactivation by the products of the reaction rather than by inhibiting the breakdown of hydrogen peroxide by catalase (EC 1.11.1.6). It has also been shown that tyrosine acted both as an activator of uterine peroxidase and as a water-soluble acceptor for the metabolites of estradiol. The ability of tyrosyl peptides to form conjugates with estradiol was influenced by the other amino acids and decreased with the number of adjacent tyrosyl residues.