[Immunochemical similarity of GTP-binding proteins of various systems].

It was found that antibodies specifically raised against GTP-binding proteins of bovine retina photoreceptor membranes block the inhibiting effect of estradiol on phosphodiesterase from human and rat uterus cytosol and prevent the combined effect of catecholamines and guanylyl-5'-imidodiphosphate on rat skeletal muscle adenylate cyclase. Using double radial immunodiffusion, it was demonstrated that the antibodies form a precipitating complex with purified tubulin from bovine brain as well as with retinal preparations obtained from the visual organs of ox, pig, rat, frog, some fish species and one reptile species. No appearance of a precipitation band was observed, when retinal preparations of invertebrates (squid, octopus) were used as antigens. The antibodies interacted with the alpha- and beta-subunits of GTP-binding proteins of bovine retinal photoreceptor membranes.