Stereospecific binding of propranolol and catecholamines to the beta-adrenergic receptor.
The stereospecificity of the beta-adrenergic receptor of turkey erythrocyte ghosts was studied. Binding of the specific beta-adrenergic antagonist, propranolol, was found to occur exclusively with the l-stereoisomer. The stereospecificity of catecholamine binding was determined by assaying the ability of the catecholamines to displace [(3)H]propranolol. Binding of the catecholamines was also found to be stereospecific for the l-stereoisomers. Furthermore, the d-stereoisomers do not compete with the l form for binding. Using this displacement technique, we were able to calculate the dissociation constants for l-epinephrine, l-norepinephrine, and l-isoproterenol from the beta-receptor and compare these values to the apparent dissociation constants obtained from the direct activation of adenylate cyclase (EC 4.6.1.1) by these catecholamines.
D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D004837:Epinephrine / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D007700:Kinetics; D009638:Norepinephrine / Q000378:metabolism; D011433:Propranolol / Q000378:metabolism*; D011941:Receptors, Adrenergic; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014316:Tritium; D014422:Turkeys
D002395:Catecholamines; D011941:Receptors, Adrenergic; D014316:Tritium; D011433:Propranolol; D009638:Norepinephrine; D004837:Epinephrine