title: Transformation of the rat uterine estrogen receptor after partial purification.
abstract: Warming crude ratuterine cytosol after the addition of [3H] estradiol accelerates the association of the 4-S estrogen-binding protein with a second macromolecule, resulting in the formation of the 5-S estrogen-binding protein. To determine whether the 5-S estrogen-binding protein consists of two similar or dissimilar subunits, uterine cytosol was subjected to a number of fractionation procedures that separate macromolecules by solubility, molecular gel sieving, sedimentation rate, ionic charge, and heat lability. Following each of these methods, the fraction containing the 4-S estrogen-binding protein was incubated at 28 degrees C; each of the these 4-S estrogen-binding protein-containing fractions retained its capacity to completely transform to the 5-S estrogen-binding protein. In samples subjected to partial purification procedures, it was necessary that the buffer contain 40 mM Tris, 60 mM Tris, 60 mM KC1, 1-10 MM dithiothreitol, and 1 M urea at pH 7.4, in order to accomplish the 4-S to 5-S estrogen-binding protein transformation at 25 degrees C. Formation of the 5-S estrogen-binding protein requires association of the 4-Estrogen-binding protein with a molecule identical to or very similar to itself.
mesh_terms: D000818:Animals; D003600:Cytosol / Q000032:analysis; D004355:Drug Stability; D004958:Estradiol / Q000378:metabolism; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D006358:Hot Temperature; D046911:Macromolecular Substances; D011485:Protein Binding; D011506:Proteins / Q000302:isolation & purification*; D051381:Rats; D011956:Receptors, Cell Surface; D012995:Solubility; D014599:Uterus / Q000378:metabolism*
chemical_list: D004967:Estrogens; D046911:Macromolecular Substances; D011506:Proteins; D011956:Receptors, Cell Surface; D004958:Estradiol