Open AccessThe Binding Characteristics and Number of β-Adrenergic Receptors on the Turkey Erythrocyte
Author(s) -
Alexander Levitzki,
Daphné Atlas,
Michael L. Steer
Publication year - 1974
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.71.7.2773
Subject(s) - propranolol , receptor , dissociation constant , adenylate kinase , cyclase , dihydroalprenolol , chemistry , adrenergic receptor , binding site , membrane , biochemistry , endocrinology , medicine , biology , antagonist , partial agonist
Turkey erythrocyte ghosts (empty membranes) possess a class of receptors that can bind both L-[3 H]isoproterenol and DL-[3 H]propranolol. The binding of [3 H]isoproterenol to these receptors occurs with a dissociation constant of 0.15 μM and can be fully inhibited by 1 μM propranolol. The binding of [3 H]propranolol occurs with a dissociation constant of 2.5 nM and can be fully inhibited by 0.2 mM DL-isoproterenol. Ligand binding is sensitive to sonication, boiling, and 8 M urea. The cells possess 500 to 1000 β-adrenergic receptors per cell. Binding of propranolol to the β-receptor was found to be stereospecific for the L stereoisomer. If one assumed a 1:1 relationship between β-adrenergic receptors and adenylate cyclase, the turnover number of this adenylate cyclase would be close to 100 min-1 .