β-Adrenergic Receptors

Recently, successful experiments on the probing of β-adrenergic receptors using radioactive reversible β-antagonists possessing high affinity such as propranolol, alprenolol, chloropractolol, and hydroxybenzylpindoloF have been reported. The binding studies have made it possible to calculate a turnover number for the hormone-stimulated adenylate cyclase. However, additional understanding as to the molecular organization of the hormone-receptor-enzyme complex in the merebrane can be tremendously advanced by developing a ligand that can bind covalently at the receptor site. A covalent affinity label for the β-receptor can become a powerful technique for the identification, characterization, and, it is hoped, the isolation of the fl-receptor. Solubilization of the β-receptor adenylate cyclase complex causes the loss of the responsiveness of the enzyme. Thus the ability to monitor the receptor by activity measurements in its solubilized state is lost. A radioactive affinity label for the β-receptor can provide one with a specific marker for the receptor even subsequent to solubilization. The chapter explains synthetic procedures of Epinephrine Derivative, Bromopractolol and Propranolol Analogs.