Affinity labeling and localization of the ATP binding site in the (Na+,K+)-ATPase

The (Na+,K+)-ATPase has been covalently labeled with oxidized ATP. The extent of oxidized ATP incorporation which inactivates the enzyme corresponds to one nucleotide site per equivalent of ouabain binding site. ATP and ADP protect against the covalent labeling by oxidized ATP; the dissociation cons...

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Bibliographic Details
Published in:The Journal of biological chemistry 1983-07, Vol.258 (13), p.8201-8205
Main Authors: Ponzio, G, Rossi, B, Lazdunski, M
Format: Article
Language:English
Subjects:
Adenosine Triphosphate - metabolism
Affinity Labels - pharmacology
Animals
Binding Sites
Dogs
Kidney Medulla - enzymology
Kinetics
Molecular Weight
Ouabain - metabolism
Peptide Fragments - analysis
Phosphorylation
Potassium Chloride - pharmacology
Protein Binding
Sodium-Potassium-Exchanging ATPase - metabolism
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Summary:The (Na+,K+)-ATPase has been covalently labeled with oxidized ATP. The extent of oxidized ATP incorporation which inactivates the enzyme corresponds to one nucleotide site per equivalent of ouabain binding site. ATP and ADP protect against the covalent labeling by oxidized ATP; the dissociation constants for the protective effects of ATP and ADP are 0.6 mM and 2.5 mM, respectively. The covalent incorporation is accelerated by K+ and by ouabain in the presence of Mg2+. The site of incorporation of oxidized ATP is located on a Mr = 58,000 fragment situated at the COOH-terminal end of the Mr = 94,000 alpha chain, while the phosphorylation site and the ouabain site are in the other (NH2-terminal) part of the chain.
ISSN:0021-9258
1083-351X
DOI:10.1016/S0021-9258(20)82049-3