title: An analysis of the decrease in the assayed level of charged bovine estrogen receptor observed at physiological ionic strength.
abstract: Lower assayed levels of heifer uterine estrogen receptor (ER) occur at physiologic ionic strength when ER is separated from [3H]estradiol by Dextran-coated charcoal treatments, or by gel filtration on Sephadex or polyacrylamide resins. The assayed level of charged ER in buffers containing 150-200 mM ionic strength is approximately one-half that of ER levels assayed in buffers either at 0-50 or 400-450 mM ionic strength. Treatment of ER with trypsin or molybdate eliminates this observed reduction. Evidence is presented that the decrease results from a preferential adsorption of ER to the assay resins at 150-200 mM ionic strength. This adsorption is likely to be mediated by a hydrophobic region of the ER, which is removed by trypsin cleavage.
authors.forename: F V
authors.initials: FV
authors.lastname: Peale
authors.forename: J
authors.initials: J
authors.lastname: Bond
authors.forename: R
authors.initials: R
authors.lastname: Hilf
authors.forename: R
authors.initials: R
authors.lastname: Bambara
mesh_terms: D000180:Acrylic Resins; D000327:Adsorption; D000818:Animals; D002417:Cattle; D002606:Charcoal; D002850:Chromatography, Gel; D003911:Dextrans; D005260:Female; D009994:Osmolar Concentration; D011960:Receptors, Estrogen / Q000032:analysis*; D014599:Uterus / Q000032:analysis
chemical_list: D000180:Acrylic Resins; D003911:Dextrans; D011960:Receptors, Estrogen; C016680:polyacrylamide gels; D002606:Charcoal