The cardiac glycoside receptor: its properties and its correlation to nucleotide binding sites, phosphointermediate, and (Na++K+)-ATPase activity.
Binding of ouabain to its receptor is followed by a directly proportional inhibition of (Na++K+)-ATPase. The stoichiometry of nucleotide binding site, phosphate acceptor site, ouabain binding site in (Na++K+)-ATPase is 1:1:1. Inactivation of (Na++K+)-ATPase by S-[2,4-Dinitrophenyl]-6-mercaptopurine riboside-5'-triphosphate, which probably forms a thioether derivative of ATP with the enzyme, results in the appearance of a low affinity binding site. It is concluded that the covalently bound ATP fixes the enzyme in a E1 conformational state which is characterized by a low affinity for ouabain.
D000244:Adenosine Diphosphate / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000201:enzymology; D002417:Cattle; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D009124:Muscle Proteins / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000378:metabolism; D010042:Ouabain / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D011485:Protein Binding; D011685:Purine Nucleotides / Q000494:pharmacology; D011955:Receptors, Drug / Q000187:drug effects; D012964:Sodium / Q000494:pharmacology
D009124:Muscle Proteins; D009943:Organophosphorus Compounds; D011685:Purine Nucleotides; D011955:Receptors, Drug; D010042:Ouabain; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases; D011188:Potassium