title: High-performance and ion-exchange chromatography and chromatofocusing of the human uterine progesterone receptor: its application to the identification of 21-[3H]dehydro Org 2058-labelled receptor.
abstract: Two independent lines of evidence were used to identify the human uterine progesterone receptor. First, three differently tritiated progestogens (Org 2058, R 5020, progesterone) were used for reversible labelling of the receptor. Secondly, the highly potent affinity label 21-[3H]dehydro Org 2058 was used to label covalently the steroid-specific binding site of the receptor. The labelled cytosols were chromatographed on a Mono Q high-performance anion-exchange column in the absence or presence of a high molar excess of the respective unlabelled competitor steroids. In the case of 21-[3H]dehydro Org 2058, Org 2058 was used as the unlabelled competitor. After elution with a NaCl gradient, the radioactivity was determined in each fraction and the elution profiles (absorption, A at 280 nm; radioactivity, dpm) were superimposed. Free steroid was eluted with the washing buffer. When the NaCl gradient was performed, two peaks of radioactivity were located. The specifically protein-bound radioactivity was eluted at 0.08 M NaCl. Two non-specific steroid-binding entities were eluted at 0.1 and 0.22 M NaCl, the second of which was identified as albumin. The elution profiles of tritiated progesterone, R 5020, Org 2058 and the affinity label 21-dehydro Org 2058 were identical. In a second set of experiments, Org 2058- and 21-dehydro Org 2058-labelled cytosols were subjected to high-performance liquid chromatography on a Mono P high-performance chromatofocusing column in the absence or presence of a high molar excess of unlabelled Org 2058. After elution with Polybuffer 74, only one specifically labelled protein (pH 6.4) was detected. When the Mono P-purified receptor was submitted to sodium dodecyl sulphate polyacrylamide gel electrophoresis, two labelled polypeptides with Mr = 45,000 and 27,000 were detectable.
mesh_terms: D001667:Binding, Competitive; D055598:Chemical Phenomena; D002621:Chemistry; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003600:Cytosol / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007525:Isoelectric Focusing; D011282:Pregnenediones / Q000032:analysis* / Q000138:chemical synthesis; D011980:Receptors, Progesterone / Q000302:isolation & purification*; D014599:Uterus / Q000032:analysis*
chemical_list: D011282:Pregnenediones; D011980:Receptors, Progesterone; C020175:16 alpha-ethyl-21-hydroxy-19-nor-4-pregnene-3,20-dione; C042857:16 alpha-ethyl-19-nor-4-pregnene-3,20-dione-21-al