Binding of a single Rb+ increases Na+/K +-ATPase, activating dephosphorylation without stoichiometric occlusion
We used partially purified Na+/K+-ATPase from pig kidney to study dephosphorylation, occlusion, and ATPase activity in the same enzyme preparation and in media of identical composition containing 10 μM ATP and different concentrations of Rb+, used as a K+ congener. The experiments were performed usi...
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2006
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v281_n23_p15721_Kaufman http://hdl.handle.net/20.500.12110/paper_00219258_v281_n23_p15721_Kaufman |
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paper:paper_00219258_v281_n23_p15721_Kaufman2023-06-08T14:43:27Z Binding of a single Rb+ increases Na+/K +-ATPase, activating dephosphorylation without stoichiometric occlusion Adenosinetriphosphate Biochemistry Biological organs Hydrolysis Rubidium Sodium Stoichiometry ATP hydrolysis ATPase Dephosphorylation Stoichiometric occlusion Enzyme kinetics adenosine triphosphatase adenosine triphosphatase (potassium sodium) rubidium ion animal tissue article binding affinity controlled study enzyme activity hydrolysis nonhuman occlusion priority journal protein dephosphorylation steady state stoichiometry swine Animals Kidney Kinetics Na(+)-K(+)-Exchanging ATPase Phosphorylation Protein Binding Rubidium Swine Sus scrofa We used partially purified Na+/K+-ATPase from pig kidney to study dephosphorylation, occlusion, and ATPase activity in the same enzyme preparation and in media of identical composition containing 10 μM ATP and different concentrations of Rb+, used as a K+ congener. The experiments were performed using a rapid-mixing apparatus with a time resolution of 3.5 ms. The main findings were as follows. (i) At sufficiently low Rb+ concentration the initial rate of dephosphorylation was higher than that of occlusion, (ii) as [Rb+] tended to zero the slope of the time course of occlusion but not that of the time course of dephosphorylation approached zero and, (iii) as Rb+ concentration increased, ATPase activity first increased and, after passing through a maximum, tended to a value that was lower than that observed in media without Rb+. None of these results is compatible with the currently held idea that binding of a single Rb+ to the E2P conformer of the ATPase does not modify the rate of dephosphorylation and strongly suggest that a single Rb+ does promote dephosphorylation through a mechanism that is not stoichiometrically coupled to Rb+ occlusion. If this mechanism is included in the currently accepted scheme for ATP hydrolysis by the Na+/K+-ATPase, a reasonable prediction of the experimental results is obtained. © 2006 by The American Society for Biochemistry and Molecular Biology, Inc. 2006 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v281_n23_p15721_Kaufman http://hdl.handle.net/20.500.12110/paper_00219258_v281_n23_p15721_Kaufman |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Adenosinetriphosphate Biochemistry Biological organs Hydrolysis Rubidium Sodium Stoichiometry ATP hydrolysis ATPase Dephosphorylation Stoichiometric occlusion Enzyme kinetics adenosine triphosphatase adenosine triphosphatase (potassium sodium) rubidium ion animal tissue article binding affinity controlled study enzyme activity hydrolysis nonhuman occlusion priority journal protein dephosphorylation steady state stoichiometry swine Animals Kidney Kinetics Na(+)-K(+)-Exchanging ATPase Phosphorylation Protein Binding Rubidium Swine Sus scrofa |
| spellingShingle |
Adenosinetriphosphate Biochemistry Biological organs Hydrolysis Rubidium Sodium Stoichiometry ATP hydrolysis ATPase Dephosphorylation Stoichiometric occlusion Enzyme kinetics adenosine triphosphatase adenosine triphosphatase (potassium sodium) rubidium ion animal tissue article binding affinity controlled study enzyme activity hydrolysis nonhuman occlusion priority journal protein dephosphorylation steady state stoichiometry swine Animals Kidney Kinetics Na(+)-K(+)-Exchanging ATPase Phosphorylation Protein Binding Rubidium Swine Sus scrofa Binding of a single Rb+ increases Na+/K +-ATPase, activating dephosphorylation without stoichiometric occlusion |
| topic_facet |
Adenosinetriphosphate Biochemistry Biological organs Hydrolysis Rubidium Sodium Stoichiometry ATP hydrolysis ATPase Dephosphorylation Stoichiometric occlusion Enzyme kinetics adenosine triphosphatase adenosine triphosphatase (potassium sodium) rubidium ion animal tissue article binding affinity controlled study enzyme activity hydrolysis nonhuman occlusion priority journal protein dephosphorylation steady state stoichiometry swine Animals Kidney Kinetics Na(+)-K(+)-Exchanging ATPase Phosphorylation Protein Binding Rubidium Swine Sus scrofa |
| description |
We used partially purified Na+/K+-ATPase from pig kidney to study dephosphorylation, occlusion, and ATPase activity in the same enzyme preparation and in media of identical composition containing 10 μM ATP and different concentrations of Rb+, used as a K+ congener. The experiments were performed using a rapid-mixing apparatus with a time resolution of 3.5 ms. The main findings were as follows. (i) At sufficiently low Rb+ concentration the initial rate of dephosphorylation was higher than that of occlusion, (ii) as [Rb+] tended to zero the slope of the time course of occlusion but not that of the time course of dephosphorylation approached zero and, (iii) as Rb+ concentration increased, ATPase activity first increased and, after passing through a maximum, tended to a value that was lower than that observed in media without Rb+. None of these results is compatible with the currently held idea that binding of a single Rb+ to the E2P conformer of the ATPase does not modify the rate of dephosphorylation and strongly suggest that a single Rb+ does promote dephosphorylation through a mechanism that is not stoichiometrically coupled to Rb+ occlusion. If this mechanism is included in the currently accepted scheme for ATP hydrolysis by the Na+/K+-ATPase, a reasonable prediction of the experimental results is obtained. © 2006 by The American Society for Biochemistry and Molecular Biology, Inc. |
| title |
Binding of a single Rb+ increases Na+/K +-ATPase, activating dephosphorylation without stoichiometric occlusion |
| title_short |
Binding of a single Rb+ increases Na+/K +-ATPase, activating dephosphorylation without stoichiometric occlusion |
| title_full |
Binding of a single Rb+ increases Na+/K +-ATPase, activating dephosphorylation without stoichiometric occlusion |
| title_fullStr |
Binding of a single Rb+ increases Na+/K +-ATPase, activating dephosphorylation without stoichiometric occlusion |
| title_full_unstemmed |
Binding of a single Rb+ increases Na+/K +-ATPase, activating dephosphorylation without stoichiometric occlusion |
| title_sort |
binding of a single rb+ increases na+/k +-atpase, activating dephosphorylation without stoichiometric occlusion |
| publishDate |
2006 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v281_n23_p15721_Kaufman http://hdl.handle.net/20.500.12110/paper_00219258_v281_n23_p15721_Kaufman |
| _version_ |
1768544026080837632 |