scholarly journals Predictive QSPR modeling of the acidic dissociation constant (pKa) of phenols in different solvents

2009 ◽  
Vol 22 (3) ◽  
pp. 186-196 ◽  
Author(s):  
Kunal Roy ◽  
Paul L. A. Popelier
Keyword(s):  
Dissociation Constant ◽  
Acidic Dissociation ◽  
Qspr Modeling ◽  
Acidic Dissociation Constant

QSTR mathematical models for the toxicity of aliphatic carboxylic acids on tetrahymena pyriformis

2013 ◽  
Vol 22 (2) ◽  
Author(s):  
Zoița Mărioara Berinde
Keyword(s):  
Dissociation Constant ◽  
Carboxylic Acids ◽  
Aquatic Toxicity ◽  
Tetrahymena Pyriformis ◽  
Refraction Index ◽  
Linear Regression Models ◽  
Acidic Dissociation ◽  
Growth Assay ◽  
Aliphatic Carboxylic Acids ◽  
Acidic Dissociation Constant

The present work represents an attempt to improve QSTR models for aquatic toxicity of 3838 aliphatic carboxylic acids tested in the Tetrahymena pyriformis population growth assay, using the topological index ZEP and the following nine main electrotopological and molecular descriptors: acidic dissociation constant, 1-octanol/water partition coefficient, the energy of the lowest unoccupied molecular orbital, acidic dissociation constant, molar refractivity, refraction index, surface tension, polarizability and, electrotopological states. Several different relations between toxicity [loglog(IGC50-1)] and the molecular and topological properties were examined, and a group of multiple linear regression models with high fitness scores were generated.

Influence of certain urinary solutes on acidic dissociation constant of ammonium at 37°C

1960 ◽  
Vol 15 (1) ◽  
pp. 125-127 ◽  
Author(s):  
Norman Bank ◽  
William B. Schwartz
Keyword(s):  
Ionic Strength ◽  
Dissociation Constant ◽  
High Concentration ◽  
Acidic Dissociation ◽  
Discernible Effect ◽  
Hückel Theory ◽  
Acidic Dissociation Constant

The acidic dissociation constant (pKa ' ) of ammonium was studied at 37 °C over a physiologic range of ionic strength. It was demonstrated that certain ions commonly found in high concentration in urine had no discernible effect on the pka' other than that resulting from their contribution to ionic strength. Urea in a concentration of 0.5 moles/l. had no significant effect on pka '. The data are taken to indicate that in urines of usual composition, ammonium pka ' should closely follow the predictions of Debye-Hückel theory. Submitted on June 19, 1959

Plasminogen-Plasmin System IX. Specific Binding of Tranexamic Acid to Plasmin

1975 ◽  
Vol 33 (03) ◽  
pp. 573-585 ◽  
Author(s):  
Masahiro Iwamoto
Keyword(s):  
Tranexamic Acid ◽  
Affinity Chromatography ◽  
Dissociation Constant ◽  
Factor Xiii ◽  
Specific Binding ◽  
The Other ◽  
Inhibitory Mechanism ◽  
Binding Studies ◽  
Similar Affinity ◽  
Fibrin Structure

SummaryInteractions between tranexamic acid and protein were studied in respect of the antifibrinolytic actions of tranexamic acid. Tranexamic acid did neither show any interaction with fibrinogen or fibrin, nor was incorporated into cross-linked fibrin structure by the action of factor XIII. On the other hand, tranexamic acid bound to human plasmin with a dissociation constant of 3.5 × 10−5 M, which was very close to the inhibition constant (3.6 × 10−5 M) for this compound in inhibiting plasmin-induced fibrinolysis. The binding site of tranexamic acid on plasmin was not the catalytic site of plasmin, because TLCK-blocked plasmin also showed a similar affinity to tranexamic acid (the dissociation constant, 2.9–4.8 × 10−5 M).In the binding studies with the highly purified plasminogen and TLCK-plasmin preparations which were obtained by affinity chromatography on lysine-substituted Sepharose, the molar binding ratio was shown to be 1.5–1.6 moles tranexamic acid per one mole protein.On the basis of these and other findings, a model for the inhibitory mechanism of tranexamic acid is presented.

The Binding of Calcium Ions to Bovine Factor X by Rate Dialysis

1978 ◽  
Vol 40 (02) ◽  
pp. 350-357
Author(s):  
Robert H Yue ◽  
Menard M Gertler
Keyword(s):  
Molecular Weight ◽  
Dissociation Constant ◽  
Calcium Ions ◽  
Activation Process ◽  
Factor X ◽  
The Real ◽  
High Affinity ◽  
Binding Data ◽  
Sequential Mechanism ◽  
Bovine Factor

SummaryThe binding of Ca+2 to bovine factor X (molecular weight of 74,000) (Yue und Gertler 1977) was studied by the technique of rate dialysis and with the use of 45Ca+2. The binding data are consistent with a model of sequential mechanism. One mole of Ca+2 binds to the glycoprotein with a dissociation constant of 5.2 × 10-5 M and an additional 39 ± 4 moles of Ca+2 bind to this zymogen with a dissociation constant of 3.7 × 10-3M. The binding of the high affinity Ca+2 causes a functionally significant change in the zymogen, and (calcium) (factor X) complex is the real substrate in the activation process by the protease in Russell’s viper venom.

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