[Identification of a photolabelled site of the plasma binding protein for testosterone and estradiol (SBP) using tritiated 17 beta-hydroxy- 4,6-androstadien-3-one]

C R Acad Sci III. 1988;307(7):391-6.
[Article in French]


The testosterone-estradiol binding protein (sex binding protein = SBP), immunopurified from human placental blood, was photolabelled by irradiation at lambda greater than 300 mm in the presence of tritiated 17 beta-hydroxy-androsta-4,6-dien-3-one. High-performance reverse-phase liquid chromatography of tryptic peptides, showed two main peaks of radioactivity. Sequence determination of these two fractions indicated that the radioactivity was associated with an undetectable amino-acid preceded either by the sequence His-Pro-Ile (major peak) or Arg-His-Pro-Ile at the N-terminal site and bearing Arg as C-terminal amino-acid. Comparison with the sequence reported for human SBP (K.A. Walsh et al., Biochemistry, 25, 1986, pp. 7584-7590) suggested that radioactive labelling was localized on the Met-139 residue of the hexapeptide Arg-His-Pro-Ile-Met-Arg (fragment 135-140).

Publication types

  • English Abstract

MeSH terms

  • Affinity Labels
  • Amino Acid Sequence
  • Binding Sites
  • Chromatography, High Pressure Liquid
  • Female
  • Humans
  • Molecular Sequence Data
  • Peptide Fragments
  • Photochemistry
  • Placenta / metabolism
  • Pregnancy
  • Sex Hormone-Binding Globulin / metabolism*
  • Testosterone / analogs & derivatives*
  • Testosterone / metabolism
  • Tritium
  • Trypsin


  • Affinity Labels
  • Peptide Fragments
  • Sex Hormone-Binding Globulin
  • Tritium
  • 6-dehydrotestosterone
  • Testosterone
  • Trypsin