scholarly journals Phosphorylation by inorganic phosphate of sodium plus potassium ion transport adenosine triphosphatase. Four reactive states

1975 ◽  
Vol 250 (2) ◽  
pp. 691-701 ◽  
Author(s):  
R L Post ◽  
G Toda ◽  
F N Rogers
Keyword(s):  
Ion Transport ◽  
Inorganic Phosphate ◽  
Adenosine Triphosphatase ◽  
Potassium Ion ◽  
Potassium Ion Transport

scholarly journals Equilibrium of Phosphointermediates of Sodium and Potassium Ion Transport Adenosine Triphosphatase

1997 ◽  
Vol 109 (5) ◽  
pp. 537-554 ◽  
Author(s):  
Kuniaki Suzuki ◽  
Robert L. Post
Keyword(s):  
Ion Transport ◽  
Rate Constants ◽  
Adenosine Triphosphatase ◽  
Reaction System ◽  
Potassium Ion ◽  
Hydrolysis Rate ◽  
Decay Kinetics ◽  
Potassium Ion Transport ◽  
Pool Model ◽  
Sodium And Potassium

Sodium and potassium ion transport adenosine triphosphatase accepts and donates a phosphate group in the course of its reaction sequence. The phosphorylated enzyme has two principal reactive states, E1P and E2P. E1P is formed reversibly from ATP in the presence of Na+ and is precursor to E2P, which equilibrates with Pi in the presence of K+. We studied equilibrium between these states at 4°C and the effect of Na+ on it. To optimize the reaction system we used a Hofmeister effect, replacing the usual anion, chloride, with a chaotropic anion, usually nitrate. We phosphorylated enzyme from canine kidney with [32P]ATP. We estimated interconversion rate constants for the reaction E1P ⇌ E2P and their ratio. To estimate rate constants we terminated phosphorylation and observed decay kinetics. We observed E1P or E2P selectively by adding K+ or ADP respectively. K+ dephosphorylates E2P leaving E1P as observable species; ADP dephosphorylates E1P leaving E2P as observable species. We fitted a 2-pool model comprising two reactive species or a twin 2-pool model, comprising a pair of independent 2-pool models, to the data and obtained interconversion and hydrolysis rate constants for each state. Replacing Na+ with Tris+ or lysine+ did not change the ratio of interconversion rate constants between E1P and E2P. Thus Na+ binds about equally strongly to E1P and E2P. This conclusion is consistent with a model of Pedemonte (1988. J. Theor. Biol. 134:165–182.). We found that Na+ affected another equilibrium, that of transphosphorylation between ATP·dephosphoenzyme and ADP·E1P. We used the reactions and model of Pickart and Jencks (1982. J. Biol. Chem. 257:5319–5322.) to generate and fit data. Decreasing the concentration of Na+ 10-fold shifted the equilibrium constant 10-fold favoring ADP·E1P over ATP·dephosphoenzyme. Thus Na+ can dissociate from E1P·Na3. Furthermore, we found two characteristics of Hofmeister effects on this enzyme.

Potassium Ion Transport by Valinomycin across a Hg-Supported Lipid Bilayer

2005 ◽  
Vol 127 (38) ◽  
pp. 13316-13323 ◽  
Author(s):  
Lucia Becucci ◽  
Maria Rosa Moncelli ◽  
Renate Naumann ◽  
Rolando Guidelli
Keyword(s):  
Ion Transport ◽  
Lipid Bilayer ◽  
Potassium Ion ◽  
Supported Lipid Bilayer ◽  
Potassium Ion Transport

KCNQ5 Participates in Form Deprivation Myopia by Regulating Potassium Ion Transport Pathway

2021 ◽  
Author(s):  
Qin Yang ◽  
Qingqing Tan ◽  
Changjun Lan ◽  
Bozhen Lv ◽  
Guimei Zhou ◽  
...  
Keyword(s):  
Ion Transport ◽  
Potassium Ion ◽  
Transport Pathway ◽  
Potassium Ion Transport

scholarly journals Inhibition of Glycolysis Alters Potassium Ion Transport and Mitochondrial Redox Activity in Rat Brain

1988 ◽  
Vol 8 (6) ◽  
pp. 857-865 ◽  
Author(s):  
Cesar N. Raffin ◽  
Thomas J. Sick ◽  
Myron Rosenthal
Keyword(s):  
Ion Transport ◽  
Iodoacetic Acid ◽  
Potassium Ion ◽  
Redox Activity ◽  
Extracellular Potassium ◽  
Potassium Ion Transport ◽  
Ion Activity ◽  
Inhibition Of Glycolysis ◽  
Glycolytic Inhibitor ◽  
Active Processes

To examine the relationships between brain glycolysis, ion transport, and mitochondrial reduction/oxidation (redox) activity, extracellular potassium ion activity (K+0) and redox shifts of cytochrome oxidase (cytochrome a,a3) were recorded previous to and during superfusion of rat cerebral cortex with the glycolytic inhibitor iodoacetic acid (IAA). IAA produced oxidation of cytochrome a,a3, increased local oxygenation, increased K+0, and, in response to neuronal activation, slowed rates of K+0 reaccumulation. Rates of rereduction of cytochrome a,a3, after the oxidation of this cytochrome by stimulation, were also slowed by IAA. These effects of IAA demonstrate the dependence of K+0 reaccumulation on the integrity of glycolysis, support the concept that active processes are involved in brain ion transport, and suggest a link between ATP supplied by glycolysis and ion transport activity. These data are also compatible with the suggestion that residual dysfunctions after brain ischemia result from derangements in glycolytic functioning rather than from limitations in oxygen availability or oxidative metabolic activity.

scholarly journals Energetics of Potassium Ion Transport in Aplysia Gut

2002 ◽  
Vol 19 (6) ◽  
pp. 629-632 ◽  
Author(s):  
George A. Gerencser ◽  
Stanley Y. Loo ◽  
Kuuleialoha M. Cornette ◽  
Jianliang Zhang
Keyword(s):  
Ion Transport ◽  
Potassium Ion ◽  
Potassium Ion Transport
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