title: Binding of 1 Rb+ accelerates dephosphorylation of the Na+,K+-ATPase without leading to Rb+ occlusion.
abstract: In steady-state conditions and for concentrations of the K(+)-congener Rb(+) less than 2.5 mM, Rb(+)-dependent ATPase activity is significantly higher than the steady-state rate of breakdown of Rb(+)-occluded states, a discrepancy that disappears at sufficiently high [Rb(+)]. Direct experimental evidence is provided that supports the explanation that the binding of a single Rb(+) to the phosphoenzyme conformer E(2)P accelerates dephosphorylation without leading to the occlusion of the cation.
authors.affiliation: Instituto de Química y Fisicoquímica Biológicas and Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Argentina. sbkauf@qb.ffyb.uba.ar
authors.forename: Sergio B
authors.initials: SB
authors.lastname: Kaufman
authors.forename: Rodolfo M
authors.initials: RM
authors.lastname: González-Lebrero
authors.forename: Patricio J
authors.initials: PJ
authors.lastname: Garrahan
authors.forename: Rolando C
authors.initials: RC
authors.lastname: Rossi
mesh_terms: D000818:Animals; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D010766:Phosphorylation; D012413:Rubidium / Q000493:pharmacokinetics* / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013552:Swine
chemical_list: D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium