title: The binding characteristics and number of beta-adrenergic receptors on the turkey erythrocyte.
abstract: 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 muM and can be fully inhibited by 1 muM 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 beta-adrenergic receptors per cell. Binding of propranolol to the beta-receptor was found to be stereospecific for the L stereoisomer. If one assumed a 1:1 relationship between beta-adrenergic receptors and adenylate cyclase, the turnover number of this adenylate cyclase would be close to 100 min(-1).
mesh_terms: D000262:Adenylyl Cyclases / Q000096:biosynthesis; D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism; D004912:Erythrocytes / Q000201:enzymology / Q000378:metabolism*; D006358:Hot Temperature; D007545:Isoproterenol / Q000378:metabolism; D008024:Ligands; D011433:Propranolol / Q000378:metabolism; D011485:Protein Binding; D011941:Receptors, Adrenergic; D014316:Tritium; D014422:Turkeys / Q000378:metabolism*; D014461:Ultracentrifugation; D014508:Urea / Q000494:pharmacology
chemical_list: D008024:Ligands; D011941:Receptors, Adrenergic; D014316:Tritium; D014508:Urea; D011433:Propranolol; D000262:Adenylyl Cyclases; D007545:Isoproterenol; D004837:Epinephrine