title: Proteolytic activity of the purified hormone-binding subunit in the estrogen receptor.
abstract: The hormone-binding subunit of the calf uterus estradiol receptor was purified as a hormone-free molecule. Immunoaffinity chromatography with a specific monoclonal antibody was used as the final step. The purified subunit was specifically labeled by radioactive diisopropyl fluorophosphate. The diisopropyl fluorophosphate-labeled amino acid was serine. The purified receptor was able to release the fluorogenic or chromogenic group from synthetic peptides containing phenylalanine at the carboxyl terminus. This occurred only in the presence of estradiol and was hampered by aprotinin and diisopropyl fluorophosphate. Estradiol-dependent hydrolytic activity was also found in the eluate from gel slices after SDS/PAGE of purified receptor. This activity comigrated with the renaturable estradiol-binding activity. The estradiol antagonists 4-hydroxytamoxifen and ICI 164,384 as well as other steroid hormones were unable to activate this hydrolytic activity.
authors.affiliation: Istituto di Patologia Generale ed Oncologia, III Cattedra, I Facoltà di Medicina e Chirurgia, Naples, Italy.
authors.forename: A M
authors.initials: AM
authors.lastname: Molinari
authors.forename: C
authors.initials: C
authors.lastname: Abbondanza
authors.forename: I
authors.initials: I
authors.lastname: Armetta
authors.forename: N
authors.initials: N
authors.lastname: Medici
authors.forename: S
authors.initials: S
authors.lastname: Minucci
authors.forename: B
authors.initials: B
authors.lastname: Moncharmont
authors.forename: V
authors.initials: V
authors.lastname: Nigro
authors.forename: G A
authors.initials: GA
authors.lastname: Puca
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007611:Aprotinin / Q000494:pharmacology; D002417:Cattle; D002863:Chromogenic Compounds / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism*; D004958:Estradiol / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D005260:Female; D006868:Hydrolysis; D007531:Isoflurophate / Q000378:metabolism / Q000494:pharmacology; D008969:Molecular Sequence Data; D053284:Polyunsaturated Alkamides; D011960:Receptors, Estrogen / Q000302:isolation & purification / Q000378:metabolism*; D013629:Tamoxifen / Q000031:analogs & derivatives / Q000494:pharmacology; D014599:Uterus / Q000737:chemistry
chemical_list: D002863:Chromogenic Compounds; D004965:Estrogen Antagonists; D053284:Polyunsaturated Alkamides; D011960:Receptors, Estrogen; D013629:Tamoxifen; D007531:Isoflurophate; C016601:afimoxifene; D004958:Estradiol; C051781:ICI 164384; D007611:Aprotinin; D010450:Endopeptidases