title: Human beta-adrenergic receptors. Simultaneous purification of beta 1- and beta 2-adrenergic-receptor peptides.
abstract: Beta-Adrenergic receptors from basal membranes of human placenta were purified from digitonin extracts by sequential rounds of affinity chromatography, hydrophobic chromatography, ion-exchange chromatography and steric-exclusion h.p.l.c. Basal membranes display both beta 1- and beta 2-adrenergic receptors, in the ratio 65:35. Affinity chromatography, hydrophobic chromatography on heptylamine-Sepharose and ion-exchange chromatography on DEAE-Sephacel removed most of the contaminating proteins, and final purification of the receptor to apparent homogeneity was achieved by steric-exclusion h.p.l.c. The purified receptors showed Mr 67000 on SDS/polyacrylamide-gel electrophoresis under reducing conditions. Specific binding of radioligand to the purified beta-adrenergic receptors displayed stereoselectivity, and the agonist competition profiles demonstrated the presence of both beta 1- and beta 2-receptors. By using the subtype-selective ligands CGP-20712A (beta 1-selective) and ICI-118,551 (beta 2-selective), the purified Mr-67000 species was shown to be composed of equivalent amounts of beta 1- and beta 2-adrenergic receptors. Affinity chromatography on Sepharose-alprenolol and sequential elution with 1 microM-CGP-20712A followed by 100 microM(-)-alprenolol permitted beta 1-adrenergic receptors to be resolved from the mixture of beta 1-/beta 2-adrenergic receptors. The pharmacologically distinct human beta 1 and beta 2-adrenergic receptors are shown to be structurally very similar peptides.
authors.affiliation: Department of Pharmacological Sciences, School of Medicine, State University of New York, Stony Brook 11794-8651.
authors.forename: S W
authors.initials: SW
authors.lastname: Bahouth
authors.forename: C C
authors.initials: CC
authors.lastname: Malbon
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D006801:Humans; D007545:Isoproterenol / Q000378:metabolism; D008024:Ligands; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011433:Propranolol / Q000378:metabolism; D011485:Protein Binding; D011943:Receptors, Adrenergic, beta / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D008024:Ligands; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D007545:Isoproterenol; D004837:Epinephrine