Preliminary characterization and partial purification of rat uterine nuclear type II Binding sites

These studies represent the first biochemical characterization and purification of nuclear type II binding sites from the rat uterus. Uterine nuclei from estradiol-implanted rats were digested with DNA'se and RNA'se, washed with Na deoxycholate-Tween 40 and extracted with 0.4 M ammonium sulfate (AmSO4). Nuclear type II sites in the AmSO4 extract eluted as a single peak during DEAE ion exchange chromatography, HPLC (Waters DEAE 5PW column) and Sephadex G-100 chromatography with a molecular weight of approximately 37K. DEAE and quercetin-sepharose affinity chromatography resulted in significant purification (greater than 800-fold) of nuclear type II sites with a 49% yield. Type II sites were not recognized by rat ER antibodies (Abbot ER-EIA kit) which immunoadsorbed ER from these preparations. These biochemical and immunological studies suggest that the ER and type II sites are likely to be different proteins.