Photoaffinity labelling of the oxytocin receptor in plasma membranes from rat mammary gland
Author(s) -
Müller Michael,
Soloff Melvyn S.,
Fahrenholz Falk
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80496-x
Subject(s) - oxytocin , photoaffinity labeling , labelling , affinity label , chemistry , receptor , agonist , tritium , vasopressin , biochemistry , lysine , membrane , oxytocin receptor , affinity labeling , neuropeptide , endocrinology , medicine , biology , amino acid , physics , nuclear physics
Plasma membranes from rat mammary gland containing a high concentration of [ 3 H]oxytocin binding sites (2.8 pmol/mg protein) were used for photoaffinity labelling experiments. Competitive binding experiments show that these receptors bind with high affinity the specific oxytocin agonist [Thr 4 , Sar 7 ]oxytocin and the analogue of 1‐deamino‐[8‐lysine]vasopressin containing a photoreactive azidobenzoyl group (Abz) at the side chain of lysine. The tritium‐labelled (50 Ci/mol) photoreactive analogue incorporated into a membrane protein with an apparent relative molecular mass of 65000 ± 3000 Da ( n = 16). The labelling of this protein was completely suppressed by an excess of oxytocin.