Acid−Base Catalysis by UDP-Galactose 4-Epimerase:  Correlations of Kinetically Measured Acid Dissociation Constants with Thermodynamic Values for Tyrosine 149†

Biochemistry ◽  
2001 ◽  
Vol 40 (22) ◽  
pp. 6699-6705 ◽  
Author(s):  
Elizabeth Berger ◽  
Abolfazl Arabshahi ◽  
Yaoming Wei ◽  
Jody F. Schilling ◽  
Perry A. Frey
Keyword(s):  
Dissociation Constants ◽  
Base Catalysis ◽  
Acid Dissociation ◽  
Acid Base ◽  
Acid Dissociation Constants

Nuclear magnetic resonance studies of the acid–base chemistry of amino acids and peptides. III. Determination of the microscopic and macroscopic acid dissociation constants of α,ω-diaminocarboxylic acids

1976 ◽  
Vol 54 (21) ◽  
pp. 3392-3400 ◽  
Author(s):  
Thomas L. Sayer ◽  
Dallas L. Rabenstein
Keyword(s):  
Chemical Shift ◽  
Dissociation Constants ◽  
Nonlinear Least Squares ◽  
Acid Dissociation ◽  
Acid Base ◽  
Acid Dissociation Constants ◽  
Ammonium Group ◽  
Titration Curves ◽  
Chemical Shift Titration ◽  
The Difference

The acid–base chemistry of 2,3-diaminopropionic acid (dap), 2,4-diaminobutyric acid (dab), ornithine (orn), and lysine (lys) has been studied by 13C and proton nmr spectroscopy. Macroscopic acid dissociation constants for titration of the two ammonium groups of each molecule have been calculated from the 13C chemical shift titration curves for the alkyl carbon atoms by nonlinear least squares curve fitting methods. Microscopic acid dissociation constants for the simultaneous titration of the two ammonium groups of protonated orn and lys have been obtained from their proton chemical shift titration curves and from the 13C titration curves for orn and dap. The results indicate that the α-ammonium group of each of these α,ω-diaminocarboxylic acids is more acidic than its ω-ammonium group, but that the difference decreases as the number of carbons separating the ammonium groups decreases so that the acidities of the two ammonium groups of dap are almost identical. Results of pmr studies of the acid–base chemistry of glycyl-L-lysine and L-lysylglycine also are reported.

scholarly journals Physico-chemical properties of N-(2-Hydroxybenzoyl)-N'-(p-Tosil) Hydrazine

2021 ◽  
Vol 11 (1) ◽  
pp. 71-81
Author(s):  
Yulia B. Elchishcheva ◽  
◽  
Ksenia S. Gorbunova ◽  
Petr T. Pavlov ◽  
◽  
...  
Keyword(s):  
Dissociation Constants ◽  
Hydrolytic Stability ◽  
Chemical Properties ◽  
Alkaline Media ◽  
Acid Dissociation ◽  
Degree Of Hydrolysis ◽  
Acid Base ◽  
Acid Dissociation Constants ◽  
Physico Chemical ◽  
Over Time

The results of a study of the physicochemical properties of N- (2-hydroxybenzoyl) -N '- (p-tosyl) hydrazine (GBSH) are presented. The solubility of the reagent in ethanol, 0.1 mol / L KOH solution, toluene, chloroform, hexane was studied by spectrophotometry, refractometry, and gravimetry. Based on the results obtained, it was shown that GBSG can be used in the processes of flotation and extraction. Acid-base equilibria in reagent solutions were studied spectrophotometrically. The obtained values of the acid dissociation constants (pKa1 = 7.93 ± 0.34; pKa2 = 10.48 ± 0.15) prove that GBSH is a weak diacid. The hydrolytic stability of the reagent was studied by the spectrophotometric method. The results of the study showed that HBHS solutions are sufficiently stable over time in alkaline media: the degree of hydrolysis within two hours is 2.35%. The surface activity of the reagent was determined by the stalagmometric method. It has been established that GBSG is a surfactant.

scholarly journals Re-evaluated data of dissociation constants of alendronic, pamidronic and olpadronic acids

2009 ◽  
Vol 7 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Alexander Boichenko ◽  
Vadim Markov ◽  
Hoan Kong ◽  
Anna Matveeva ◽  
Lidia Loginova
Keyword(s):  
Aqueous Solutions ◽  
Alendronic Acid ◽  
Dissociation Constants ◽  
Cetylpyridinium Chloride ◽  
Pamidronic Acid ◽  
Acid Dissociation ◽  
Micellar Solutions ◽  
Acid Base ◽  
Acid Dissociation Constants ◽  
Naoh Solution

AbstractThe dissociation constants of (4-amino-1-hydroxybutylidene)bisphosphonic (alendronic) acid, (3-(dimethylamino)-1-hydroxypropylidene)bisphosphonic (olpadronic) acid and (3-amino-1-hydroxypropylidene)bisphosphonic (pamidronic) acid were obtained in aqueous solutions (0.10 M KCl) and micellar solutions of cetylpyridinium chloride (0.10 M CPC) at 25.0°C. With the exception of the third dissociation constant of alendronic acid, the dissociation constants of alendronic, olpadronic and pamidronic acids in aqueous solutions matched literature data. The possibility of sodium alendronate determination by acid-base titration by NaOH solution was theoretically grounded on the basis of re-evaluated data of alendronic acid dissociation constants.

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