Ouabain- and Ca2(+)-sensitive ATPase activity of chimeric Na- and Ca-pump molecules.
Chimeric ion-pumps, consisting of the N-terminal 2/3 of the alpha 1-subunit of the ouabain-sensitive chicken Na+,K(+)-ATPase and the C-terminal 1/3 of the sarcoplasmic reticulum Ca2(+)-ATPase, were expressed in ouabain-insensitive mouse L cells. These chimeric molecules exhibited ouabain-sensitive ATPase activity very similar to that of the wild-type chicken Na+, K(+)-ATPase. This ATPase activity could be stimulated by adding Ca2+ to the assay system. These results suggest that the sites for ouabain-inhibition are restricted to the N-terminal 2/3 of the Na-pump, and the C-terminal 1/3 of the Ca-pump interacts with Ca2+.
Luckie
D B
DB
Department of Physiology, University of Virginia School of Medicine, Charlottesville 22908.
Boyd
K L
KL
Takeyasu
K
K
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology / Q000648:ultrastructure; D002645:Chickens; D002678:Chimera; D003001:Cloning, Molecular; D007700:Kinetics; D007739:L Cells / Q000201:enzymology; D046911:Macromolecular Substances; D051379:Mice; D010042:Ouabain / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D046911:Macromolecular Substances; D010042:Ouabain; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium