Evidence from oxygen-18 exchange measurements for steps involving a weak acid and a slow chemical transformation in the mechanism of phosphorylation of the gastric hydrogen ion-potassium ATPase by inorganic phosphate

Biochemistry ◽  
1989 ◽  
Vol 28 (17) ◽  
pp. 6908-6914 ◽  
Author(s):  
Larry D. Faller ◽  
Ruben A. Diaz
Keyword(s):  
Chemical Transformation ◽  
Inorganic Phosphate ◽  
Weak Acid ◽  
Hydrogen Ion ◽  
Potassium Atpase

Location of the carbohydrates present in the hydrogen ion-potassium ATPase vesicles isolated from hog gastric mucosa

Biochemistry ◽  
1990 ◽  
Vol 29 (3) ◽  
pp. 701-706 ◽  
Author(s):  
Kathleen Hall ◽  
Gonzalo Perez ◽  
Debra Anderson ◽  
Cecilia Gutierrez ◽  
Keith Munson ◽  
...  
Keyword(s):  
Gastric Mucosa ◽  
Hydrogen Ion ◽  
Potassium Atpase

scholarly journals SOME CONSEQUENCES OF THE THEORY OF MEMBRANE EQUILIBRIA

1925 ◽  
Vol 9 (1) ◽  
pp. 97-109 ◽  
Author(s):  
David I. Hitchcock
Keyword(s):  
Membrane Potential ◽  
Osmotic Pressure ◽  
Ionization Constant ◽  
Weak Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Weak Base ◽  
Acid Base ◽  
Hydrogen Ion Concentration ◽  
Pass Through

In applying Donnan's theory of membrane equilibria to systems where the non-diffusible ion is furnished by a weak acid, base, or ampholyte, certain new relations have been derived. Equations have been deduced which give the ion ratio and the apparent osmotic pressure as functions of the concentration and ionization constant of the weak electrolyte, and of the hydrogen ion concentration in its solution. The conditions for maximum values of these two properties have been formulated. It is pointed out that the progressive addition of acid to a system containing a non-diffusible weak base should not cause the value of the membrane potential to rise, pass through a maximum, and fall, but should only cause it to diminish. It is shown that the theory predicts slight differences in the effect of salts on the ion ratio in such systems, the effect increasing with the valence of the cation.

Evidence for the presence of a carbohydrate moiety in fluorescein isothiocyanate labeled fragments of rat gastric hydrogen ion-potassium ATPase

Biochemistry ◽  
1989 ◽  
Vol 28 (8) ◽  
pp. 3183-3187 ◽  
Author(s):  
Mindy M. Tai ◽  
Wha Bin Im ◽  
John P. Davis ◽  
David P. Blakeman ◽  
Heidi A. Zurcher-Neely ◽  
...  
Keyword(s):  
Fluorescein Isothiocyanate ◽  
Carbohydrate Moiety ◽  
Hydrogen Ion ◽  
Potassium Atpase

scholarly journals SOME PHYSICOCHEMICAL PROPERTIES OF DISSOCIATED SPONGE CELLS

1926 ◽  
Vol 10 (2) ◽  
pp. 239-255 ◽  
Author(s):  
P. S. Galtsoff ◽  
Vladimir Pertzoff
Keyword(s):  
Physicochemical Properties ◽  
Weak Acid ◽  
Hydrogen Ion ◽  
Acid Solutions ◽  
Average Value ◽  
Cliona Celata ◽  
Number Of Cells

1. The activity of the hydrogen ion, in a system containing 0.00280 mols of NaAc, 0.520 mols of NaCl per liter, and varied amounts of HCl or NaOH has been investigated. The average value of pK' for acetic add in this system is about 4.37. 2. The effect of the addition of various amounts of HCl and NaOH to a system containing 0.00280 mols of NaAc, 0.520 mols of NaCl, and a known number of cells of either Microciona prolifera or Cliona celata was then studied. It was found that in weak acid solutions Microciona behaves as a stronger base than Cliona, the former being practically saturated with base at a pH of 7.5. Similar behavior is shown by suspensions of cells to which no acid or base was added: the cells of Cliona are more acidic than the cells of Microciona. 3. The microscopic examinations of the cells subjected to the treatment with acid or base indicate that the cells of Microciona remain alive down to pH 4.50; the cells of Cliona sustain greater acidity,— a,t pH 3.7 they exhibit no signs of cytolysis. Tests for aggregation of these cells showed that this phenomenon is greatly inhibited even by slightly acid solutions. 4. The conclusion is drawn that the concentration of cells being equal, the suspensions of cells of Microciona and Cliona differ from each other in their physicochemical properties, the comparison being made on suspensions of specified composition.

scholarly journals Maximal Ca2+-activated force and myofilament Ca2+ sensitivity in intact mammalian hearts. Differential effects of inorganic phosphate and hydrogen ions.

1987 ◽  
Vol 90 (5) ◽  
pp. 609-623 ◽  
Author(s):  
E Marban ◽  
H Kusuoka
Keyword(s):  
Inorganic Phosphate ◽  
Hydrogen Ion ◽  
Hydrogen Ions ◽  
Intact Tissue ◽  
Fundamental Properties ◽  
Skinned Muscle ◽  
Novel Approach ◽  
Nuclear Magnetic Resonance Spectra ◽  
Maximal Pressure ◽  
The One

Myofilament Ca2+ sensitivity and maximal Ca2+-activated force are fundamental properties of the contractile proteins in the heart. Although these properties can be evaluated directly in skinned preparations, they have remained elusive in intact tissue. A novel approach is described that allows maximal Ca2+-activated force to be measured and myofilament Ca2+ sensitivity to be deduced from isovolumic pressure in intact perfused ferret hearts. Phosphorus nuclear magnetic resonance spectra are obtained sequentially to measure the intracellular inorganic phosphate (Pi) and hydrogen ion (H+) concentrations. After a period of perfusion with oxygenated, HEPES-buffered Tyrode solution, hypoxia is induced as a means of elevating [Pi]. The decline in twitch pressure can then be related to the measured increase in [Pi]. After recovery, hearts are perfused with ryanodine to enable tetanization and the measurement of maximal Ca2+-activated pressure. Hypoxia is induced once again, and maximal pressure is correlated with [Pi]. We then compare the relations between [Pi] and maximal pressure on the one hand, and [Pi] and twitch pressure on the other. If the two relations differ only by a constant scaling factor, then the decline in twitch pressure can be attributed solely to a decline in maximal pressure, with no change in myofilament sensitivity. We obtained such a result during hypoxia, which indicated that Pi accumulation decreases maximal force but does not change myofilament sensitivity. We compared these results with acidosis (induced by bubbling with 5% CO2). In contrast with Pi, the accumulation of H+ decreases twitch force primarily by shifting myofilament Ca2+ sensitivity. This approach in intact tissue has strengths and limitations complementary to those of skinned muscle experiments.

Ionic Equilibria and pH

2009 ◽  
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Pure Water ◽  
Weak Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ions ◽  
Hydrogen Ion Concentration ◽  
M 10 ◽  
Ionic Equilibria ◽  
Hydrated Protons ◽  
Dilute Aqueous Solution

Water is a weak acid. At 25°C, pure water ionizes to form a hydrogen ion and a hydroxide ion: H2O ⇋ H+ + OH− Hydration of the proton (hydrogen ion) to form hydroxonium ion is ignored here for simplicity. This equilibrium lies mainly to the left; that is, the ionization happens only to a slight extent. We know that 1 L of pure water contains 55.6 mol. Of this, only 10−7 mol actually ionizes into equal amounts of [H+] and [OH−], i.e., [H+] = [OH−] = 10−7M Because these concentrations are equal, pure water is neither acidic nor basic. A solution is acidic if it contains more hydrogen ions than hydroxide ions. Similarly, a solution is basic if it contains more hydroxide ions than hydrogen ions. Acidity is defined as the concentration of hydrated protons (hydrogen ions); basicity is the concentration of hydroxide ions. Pure water ionizes at 25°C to produce 10−7 M of [H+] and 10−7 M of [OH−]. The product Kw = [H+]×[OH−] = 10−7 M×10−7 M= 10−14 M is known as the ionic product of water. Note that this is simply the equilibrium expression for the dissociation of water. This equation holds for any dilute aqueous solution of acid, base, and salt. The pH of a solution is defined as the negative logarithm of the molar concentration of hydrogen ions. The lower the pH, the greater the acidity of the solution. Mathematically: pH=−log10[ H+] or −log10[H3O+] This can also be written as: pH = log10 1/[H+] or log10 1/[H3O+] Taking the antilogarithm of both sides and rearranging gives: [H+] = 10−pH This equation can be used to calculate the hydrogen ion concentration when the pH of the solution is known.

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