Proteolytic activity of the purified hormone-binding subunit in the estrogen receptor

A. M. Molinari, C. Abbondanza, I. Armetta, N. Medici, S. Minucci, B. Moncharmont, V. Nigro, G. A. Puca

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)4463-4467
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number10
Publication statusPublished - 1991


  • peptide substrates
  • receptor transformation
  • serine proteases
  • steroid receptor

ASJC Scopus subject areas

  • General
  • Genetics


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