title: Isolation and characterization of beta 1-adrenergic receptors from adult, rat cardiac myocytes.
abstract: The beta-receptors were isolated from rat cardiac myocytes and characterized. Isolated myocytes were prepared from adult rat hearts and characterized for viability. Membrane proteins were solubilized from myocytes with 1% Triton X-102. The solubilized membrane proteins were fractionated by DEAE-Sephacel ion exchange column chromatography. Two major protein peaks were obtained. The second protein peak sample was found to contain beta-receptors to which 125I-15-(4'-azido-3'-iodobenzyl)-carazolol (125I-ABC) was specifically bound. This sample was labeled covalently with 125I-ABC by UV irradiation. The radiolabeled sample was applied to a Sepharose CL-6B gel column. Two radiolabeled protein peaks, one with a molecular weight of approximately 570,000 and the other with a molecular weight of approximately 95,000 were found. When the 570,000-dalton complex was subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions, it was dissociated into a component with a molecular weight of 66,000. The 95,000-dalton complex was dissociated into a 58,000-dalton component upon SDS-PAGE under reducing conditions. An excess amount of isoproterenol and propranolol decreased photolabeling of the beta-receptors with 125I-ABC by 60% and 40%, respectively.
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000345:Affinity Labels / Q000378:metabolism; D000818:Animals; D001386:Azides / Q000378:metabolism; D001667:Binding, Competitive; D007545:Isoproterenol / Q000494:pharmacology; D009206:Myocardium / Q000032:analysis*; D011412:Propanolamines / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000319:Adrenergic beta-Antagonists; D000345:Affinity Labels; D001386:Azides; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C035888:4-azido-3-iodobenzylcarazolol; D011433:Propranolol; D007545:Isoproterenol