Proteins of rod outer segments of toad retina: binding with calmodulin and with GTP

Proteins of purified rod outer segments from toad retina were analysed by electrophoresis on polyacrylamide gel containing sodium dodecyl sulfate. The binding of proteins with calmodulin and with guanosine triphosphate was studied by electroblotting the proteins resolved by electrophoresis onto nitrocellulose sheets and by incubating the blots with labelled ligands. The results indicate that rod outer segments from toad retina contain nine proteins which bind to calmodulin and one protein, different from transducin, that binds to guanosine triphosphate.