Interactions of pure βγ‐subunits of G‐proteins with purified β1‐adrenoceptor

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Abstract
The role of the βγ‐subunits in the interaction of G‐proteins was examined with β1‐adrenoceptors purified from turkey erythrocytes and pure βγ‐subunits prepared from turkey erythrocytes and bovine brain. On a non‐denaturing polyacrylamide gel, the mobility of βγ‐subunits was increased when incubated with β1‐adrenoceptor and the β1‐adrenergic agonist l‐(−)‐isoproterenol, whereas on incubation with the antagonist l‐alprenolol the mobility was unchanged. Furthermore, the β1‐adrenoceptor was retarded on a Sephadex G‐50 column equilibrated with βγ‐subunits and agonist. No retardation occurred in the presence of antagonist. These data suggest a direct interaction of activated β1‐adrenoceptors with isolated βγ‐subunits of G‐proteins.