Determination of the inhibitor dissociation constant of an individual unmodified enzyme molecule in free solution

2016 ◽  
Vol 37 (15-16) ◽  
pp. 2217-2225 ◽  
Author(s):  
Jeremie J Crawford ◽  
Joshua W Hollett ◽  
Douglas B Craig
Keyword(s):  
Dissociation Constant ◽  
Free Solution ◽  
Enzyme Molecule

Determination of dissociation constant of phosphinate group in phosphinic pseudopeptides by capillary zone electrophoresis

2002 ◽  
Vol 770 (1-2) ◽  
pp. 145-154 ◽  
Author(s):  
Dušan Koval ◽  
Václav Kašička ◽  
Jiřı́ Jiráček ◽  
Michaela Collinsová ◽  
Timothy A. Garrow
Keyword(s):  
Dissociation Constant ◽  
Capillary Zone Electrophoresis ◽  
Zone Electrophoresis ◽  
Capillary Zone

Determination of Relative Stability of Urea Complexes from X-Ray Powder Diffraction Data

1960 ◽  
Vol 4 ◽  
pp. 140-150 ◽  
Author(s):  
Jack Radell ◽  
J.W. Connolly
Keyword(s):  
Dissociation Constant ◽  
Guest Molecule ◽  
Interplanar Spacing ◽  
Dynamic Equilibrium ◽  
Crystalline Complex ◽  
Guest Molecules ◽  
X Ray ◽  
Host Molecules ◽  
The Stability

AbstractUrea complexes consist of a channel made up of hydrogen-bonded urea host molecules into which a variety of guest molecules can fit to form a crystalline complex. The urea host can accommodate, one at a time, a variety of guests having the requisite size and shape. The stability of the resulting complex is a function of the properties of the guest molecule. A procedure has been devised which produces pure complex free of any uncomplexed urea or host molecules in solution. The insoluble crystalline complexes formed from the solution of urea and guest molecule in methanol established a dynamic equilibrium. When the crystals of complex are removed from the solution, dissociation to urea and guest occurs to an extent, depending upon the dissociation constant of the complex. If the dissociation constant, KD, is very low, undetectable quantities of uncomplexed urea form along with complex. If the dlissoclation constant is high, extensive amounts of urea form in the presence of complex. Characteristic interplanar spacing s are obtained for a urea complex irrespective of the guest molecule present. The pattern obtained for the hexagonal complex is completely different from the pattern obtained for tetragonal urea. X-ray examination of a homologous series of compounds gives, for each partially dissociated complex, spacings for both urea and complex. The relative intensities of urea and complex spacings permit the estimation of the stability of such a complex compared to that of other homologues.

Chromatographic Determination of Thermodynamic Acid Dissociation Constants of Tetracycline Antibiotics and Their Epimers

2019 ◽  
Vol 57 (8) ◽  
pp. 745-750
Author(s):  
İlkay Konçe ◽  
Ebru Çubuk Demiralay ◽  
Hülya Yılmaz Ortak
Keyword(s):  
Experimental Data ◽  
Dissociation Constant ◽  
Binary Mixtures ◽  
Dissociation Constants ◽  
Reversed Phase ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Chromatography Method ◽  
Ph Values

Abstract The presented study describes the development of reversed-phase liquid chromatography method using a core-shell particle column with a pentafluorophenyl stationary phase for the dissociation constant (pKa) determination of the tetracycline group antibiotics (tetracycline, oxytetracycline, chlortetracycline) and their epimers (4-epitetracycline, 4-epioxytetracycline, 4-epichlortetracycline). The pH values were measured in the acetonitrile (ACN)–water binary mixtures, used as mobile phases, instead of in water and take into account the effect of the activity coefficients. Thermodynamic acid dissociation constant (pKa1) values of studied antibiotics and their epimers were calculated using retention factor (k) at different mobile phase pH values in studied binary mixtures with ACN percentages of 20, 25, 30 and 35% (v/v). Experimental data were analyzed by using an Origin 7.0 program to fit experimental data to the nonlinear expression derived. From calculated pKa1 values, the aqueous pKa values of studied compounds were calculated by different approaches and these values were compared.

The determination of the second dissociation constant of sulfuric acid

1994 ◽  
Vol 23 (1) ◽  
pp. 75-80 ◽  
Author(s):  
P. Luts ◽  
J. Vanhees ◽  
J. Yperman ◽  
J. Mullens ◽  
L. C. Van Poucke
Keyword(s):  
Sulfuric Acid ◽  
Dissociation Constant ◽  
Second Dissociation Constant
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