scholarly journals COLOR CHANGES AMONG DYES OF THE TRIPHENYLMETHANE SERIES AS INFLUENCED BY THE HYDROGEN ION CONCENTRATION OF ACIDS OF DIFFERENT DISSOCIATION CONSTANTS. (ON CATALYSES WITH WEAK ACIDS, III.1)

1913 ◽  
Vol 35 (3) ◽  
pp. 273-281 ◽  
Author(s):  
H. C. Biddle
Keyword(s):  
Dissociation Constants ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Weak Acids ◽  
Hydrogen Ion Concentration ◽  
Color Changes

The Functional Groups of the Mg–Ca ATPase from Escherichia coli

1975 ◽  
Vol 53 (6) ◽  
pp. 658-665 ◽  
Author(s):  
Jan Ahlers ◽  
Doris Kabisch ◽  
Theodor Günther
Keyword(s):  
Escherichia Coli ◽  
Metal Ion ◽  
Experimental Error ◽  
Dissociation Constants ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
E Coli ◽  
Membrane Bound ◽  
Arginyl Residues

The influence of hydrogen ion concentration on binding and conversion of MgATP and CaATP by membrane bound and solubilized ATPase from Escherichia coli has been investigated. The reaction of enzyme (E), hydrogen ion (H+), and substrate (S) proceeds according to the following scheme, where Me is the metal ion and P is the product(s).[Formula: see text]Within experimental error, the results obtained with membrane-bound and solubilized ATPase are identical. Changing the concentration of Mg2+ ions or replacement of Mg2+ by Ca2+ ions alters the dissociation constants Kb, KHMeATP, and [Formula: see text]. The kinetics and experiments with group-specific inhibitors suggest that integrity for amino, imidazole, tyrosyl, carboxyl, and arginyl residues is required for activity of membrane-bound and solubilized E. coli ATPase.

THE HYDROLYSIS OF THE CONDENSED PHOSPHATES: II (A). THE ROLE OF THE HYDROGEN ION IN THE HYDROLYSIS OF SODIUM PYROPHOSPHATE: II (B). THE DISSOCIATION CONSTANTS OF PYROPHOSPHORIC ACID

1954 ◽  
Vol 32 (2) ◽  
pp. 174-185 ◽  
Author(s):  
J. D. McGilvery ◽  
Joan Pedley Crowther
Keyword(s):  
Dissociation Constants ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Rate Equations ◽  
Hydrogen Ion Concentration ◽  
Pyrophosphoric Acid ◽  
Condensed Phosphates ◽  
Anionic Species ◽  
Hydrolysis Of

The general rate equations for the hydrolysis of pyrophosphate anion proposed by Muus have been proved to be inapplicable over the pH range 2.0 to 11.0. A general rate equation is proposed which is based on the assumption that each anionic species of pyrophosphoric acid hydrolyzes at a rate which depends on its concentration, and that the only role of the hydrogen ion concentration is to determine the proportion of each species present in the solution. A mechanism for the hydrolysis of pyrophosphate anion is suggested.The dissociation constants of pyrophosphoric acid have been determined at 65.5 °C. for the concentration range 0.08 to 0.18 molar.

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