Biochemical and immunochemical analysis of avian beta 1 and mammalian beta 2-adrenergic receptors.

We have studied the molecular properties of avian beta 1-adrenergic receptor and human beta 2-adrenergic receptor. The turkey erythrocytes beta 1-receptor has been solubilized in active form by digitonin and has been purified to homogeneity by affinity chromatography followed by electroelution from polyacrylamide gel. The photoactivable ligand, iodocyanopindololdiazirine, labels specifically a major 45 kDa and minor 55 kDa polypeptide in turkey erythrocytes, whereas in A431, it labels two polypeptides of molecular weights 65 kDa and 55 kDa. Both types of receptors are N- and possibly O-glycosylated but the turkey beta 1 receptor has only complex carbohydrates whereas the human beta 2 receptor has in addition oligo mannosidic polysaccharidic moiety. Polyclonal and monoclonal antibodies were raised against the beta 1- and beta 2-adrenergic receptors. Polyclonal antibodies were found to mimic beta-adrenergic agonists by stimulating adenylate cyclase upon binding to the receptors. The monoclonal antibodies precipitated both intact and affinity labeled receptors which they also revealed on immunoblots.