Separation and identification of two components of an estrogen-responsive, calcium-dependent arginine esteropeptidase

Abstract Arginine esteropeptidase is an estrogen-responsive, calcium-dependent enzyme in rat uterine cytosol. It appears in increased amounts 3 h after administration of physiologic amounts of 17β-estradiol to an immature female rat. Its reaction was resolved into two parts: a calcium-dependent activation of the enzyme and a calcium-independent hydrolysis of the substrate. The esteropeptidase was separated by DEAE cellulose chromatography into two components. The properties of component A, the activator, are distinct from those of component B, the enzyme, which has the same response to inhibitors as serine proteinases. Both components are subject to estrogen control. Component A is present in significant amounts only after estrogen stimulation. Component B is increased 3-fold after estrogen stimulation. The responses of the two components to inhibitors, their different molecular weights and Chromatographic behavior and the pH optima of their reactions distinguish them from each other and from other uterine proteinases previously described.