The interaction of ATP-analogues possessing a blocked gamma-phosphate group with the sodium pump in human red cells.
1. The (Na++K+)-ATPase of red cell membranes is unable to hydrolyse ATP-analogues in which the oxygen atom linking the beta- and gamma-phosphate groups is replaced by a minusCH2minus or minusNH-bridge. 2. In resealed ghosts both these ATP-analogues support K:K exchange but not Na:K exchange. ATP supports both modes of operation of the sodium pump, whereas neither occurs without any nucleotide. 3. These results support the hypothesis that ATP is needed as a cofactor for K:K exchange to occur, and make it extremely unlikely that phosphorylation from ATP is involved.
D000227:Adenine Nucleotides / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D002462:Cell Membrane / Q000201:enzymology; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007094:Imides / Q000494:pharmacology; D066298:In Vitro Techniques; D063065:Organophosphonates / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D010710:Phosphates / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D011194:Potassium Isotopes; D012964:Sodium / Q000378:metabolism*; D012975:Sodium Isotopes
D000227:Adenine Nucleotides; D007094:Imides; D063065:Organophosphonates; D010710:Phosphates; D011194:Potassium Isotopes; D012975:Sodium Isotopes; D010042:Ouabain; D000255:Adenosine Triphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases; D011188:Potassium