pH, Ionic Strength, and Temperature Dependences of Ionization Equilibria for the Carboxyl Groups in Turkey ovomucoid Third Domain

Biochemistry ◽  
1995 ◽  
Vol 34 (14) ◽  
pp. 4714-4723 ◽  
Author(s):  
Wolfgang Schaller ◽  
Andrew D. Robertson
Keyword(s):  
Ionic Strength ◽  
Carboxyl Groups ◽  
Ovomucoid Third Domain ◽  
Temperature Dependences ◽  
Ionization Equilibria

scholarly journals The Surface of the Washed Human Erythrocyte as a Polyanion

1960 ◽  
Vol 44 (2) ◽  
pp. 251-268 ◽  
Author(s):  
G. V. F. Seaman ◽  
D. H. Heard
Keyword(s):  
Ionic Strength ◽  
Cell Membrane ◽  
Human Erythrocyte ◽  
Negative Charge ◽  
Physical Adsorption ◽  
Structural Instability ◽  
Carboxyl Groups ◽  
Charge Reduction ◽  
Tosyl Chloride ◽  
Phosphate Groups

The electrokinetic behaviour of normal erythrocytes is compared with that of trypsin-, N-bromosuccinimide-, and tosyl-treated erythrocytes. Reduction in the net negative charge with reduction in ionic strength of the suspending medium and also on treatment with N-bromosuccinimide and trypsin is discussed using a porous non-rigid polyanion as a model for the periphery of the cell membrane. It is deduced from the equivalent binding of chloride and thiocyanate ions and the absence of any effect on treatment of red cells with tosyl chloride, that normal, N-bromosuccinimide- and trypsin-treated cells are polyanionic in character. Reduction in erythrocyte charge on treatment with N-bromosuccinimide or trypsin is probably not due to the removal of phosphate groups from the interface, nor to physical adsorption of N-bromosuccinimide or trypsin. The charge reduction is probably produced by bond fission with possibly a net disappearance of carboxyl groups from the electrophoretic plane of shear either by loss from, or reorientation of, the membrane. The loss or reorientation of material associated with these carboxyl groups does not lead to any basic change in the character of the surface of the cell, nor to any obvious structural instability. The biconcave discoid form is maintained and there is no significant hemolysis of the erythrocytes even after contact with a solution of trypsin for 24 hours.

Theoretical and Experimental Analysis of Ionization Equilibria in Ovomucoid Third Domain†

Biochemistry ◽  
1998 ◽  
Vol 37 (24) ◽  
pp. 8643-8652 ◽  
Author(s):  
William R. Forsyth ◽  
Michael K. Gilson ◽  
Jan Antosiewicz ◽  
Olav R. Jaren ◽  
Andrew D. Robertson
Keyword(s):  
Experimental Analysis ◽  
Ovomucoid Third Domain ◽  
Ionization Equilibria

scholarly journals Electrokinetic properties of isolated cerebral-cortex synaptic vesicles

1973 ◽  
Vol 136 (4) ◽  
pp. 919-926 ◽  
Author(s):  
Jack McLaughlin ◽  
Kenneth R. Case ◽  
H. Bruce Bosmann
Keyword(s):  
Cerebral Cortex ◽  
Sialic Acid ◽  
Ionic Strength ◽  
Guinea Pig ◽  
Concanavalin A ◽  
Synaptic Vesicles ◽  
Carboxyl Groups ◽  
Electrokinetic Properties ◽  
Ph Dependent ◽  
Vesicle Mobility

Synaptic vesicles isolated from guinea-pig cerebral cortex had an electrophoretic mobility of −3.55μm·s-1·V-1·cm in saline–sorbitol, pH7.2, at 25°C (ionic strength 0.015g-ions/1). The mobility was pH-dependent, varied with ionic strength and indicated that the vesicular surface contained weak acidic functions with a pKa in the range 3.0–3.8. Although the vesicular surface was determined to be highly negatively charged, treatment with neuraminidase had no effect on mobility and indicated that the relatively strong carboxyl groups of sialic acid do not contribute significantly to vesicular electrokinetic properties. Treatment of synaptic vesicles with trypsin or trypsinized concanavalin A resulted in increases in mobility, but treatment with ribonuclease, deoxyribonuclease, chrondroitinase ABC or hyaluronidase had no significant effect on mobility. Mn2+or Ca2+was more effective in decreasing vesicle mobility than was Mg2+, Sr2+or Ba2+. The electrokinetic properties of the synaptic vesicle surface are discussed and contrasted with the properties of the synaptosomal membrane.

The kinetics and mechanism of the reaction between nickel(II) and dithiocarbamate ions in dimethyl sulfoxide. Evidence for the ID mechanism for a bidentate uninegative ligand

1978 ◽  
Vol 31 (12) ◽  
pp. 2581 ◽  
Author(s):  
PJ Nichols ◽  
MW Grant
Keyword(s):  
Fourier Transform ◽  
Ionic Strength ◽  
Dimethyl Sulfoxide ◽  
Excellent Agreement ◽  
Rate Constants ◽  
Second Order ◽  
Kinetics And Mechanism ◽  
First Order ◽  
Temperature Dependences ◽  
Mechanism Of The Reaction

13C Fourier-transform N.M.R. has been used to measure the rate of exchange of dimethyl sulfoxide with hexakis(dimethyl sulfoxide)nickel(II) cation. The parameters obtained, kex(25°C)(9.8�4.6) × 103 s-1, ΔH‡ 50�2 kJ mol-1 and ΔS‡ 0�4 J K-1 mol-1, are in excellent agreement with those of the most recent 1H N.M.R. study. The reaction between Ni(Me2SO)62+ and diethyldithiocarbamate (dtc-) gives only Ni(dtc)2. When dtc- is in excess, the rate of formation of Ni(dtc)2 is first order in Ni2+ and dtc-. The ionic-strength and temperature dependences of the second-order rate constants are consistent with the rate-determining formation of an unstable Ni(dtc)+ complex by an ID mechanism.

Study on a Photonic Crystal Hydrogel Material for Chemical Sensing

2015 ◽  
Vol 14 (01n02) ◽  
pp. 1460025
Author(s):  
Jia-Yu Xu ◽  
Chun-Xiao Yan ◽  
Xiao-Chun Hu ◽  
Chao Liu ◽  
Hua-Min Tang ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Ionic Strength ◽  
Chemical Modification ◽  
Chemical Sensing ◽  
Electrostatic Interactions ◽  
Carboxyl Groups ◽  
Polystyrene Spheres ◽  
Crystalline Colloidal Arrays ◽  
Crystalline Colloidal Array ◽  
Monodisperse Polystyrene

There is intense interest in the applications of photonic crystal hydrogel materials for the detection of glucose, metal ions, organophosphates and so on. In this paper, monodisperse polystyrene spheres with diameters between 100 ~ 440 nm were synthesized by emulsion polymerization. Highly charged polystyrene spheres readily self-assembled into crystalline colloidal array because of electrostatic interactions. Photonic crystal hydrogel materials were formed by polymerization of acrylamide hydrogel around the crystalline colloidal arrays of polystyrene spheres. After chemical modification of hydrogel backbone with carboxyl groups, our photonic crystals hydrogel materials are demonstrated to be excellent in response to pH and ionic strength changes.

scholarly journals BUFFER SOLUTIONS BASED ON TAURINE

2021 ◽  
Vol 26 (1(77)) ◽  
pp. 48-64
Author(s):  
T. S. Ben’kovs’ka ◽  
R. E. Khoma ◽  
A. N. Chebotaryov ◽  
A. A.-A. Ennan ◽  
L. T. Osadchiy
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Buffer Capacity ◽  
Water System ◽  
Acid Base ◽  
Buffer Zones ◽  
Base Interaction ◽  
Temperature Range ◽  
Temperature Dependences ◽  
Ph Range

The acid-base interaction in the aminoethanesulfonic acid (taurine, Tau) – potassium aminoethanesulfonate – water system was studied by pH-, redox- and conductometric methods in the temperature range 293–313 K. The ion-molecular composition of NH2CH2CH2SO3H –NH2CH2CH2SO3K – H2O system was calculated. It is shown aminoethanesulfonic acid in aqueous solutions to exist at the ratio CKOH/QTau < 0.5 mainly in the zwitterion form similar to systems with glycine, aminomethanesulfonic acid and its N‑alkylated derivatives. The content of the aminoethanesulfonate anion is directly proportional to the CKOH/QGly ratio. The studied system ionic strength and acid-base dissociation constant for the second stage of the aminoethanesulfonic acid concentration and temperature dependences were determined. The ionic strength values at the isoelectric point (mi.p.)are directly proportional to С0Tau and practically do not depend on the temperature within the error for the same series С0Tau and С0KOH .The pH limits of the buffer action are determined and the buffer capacity of these systems is estimated. It has been established that effective buffer zones of Tau aqueous solutions can to maintain acidity in the higher then physiological pH range at temperature range 293–313 K. The buffer capacity of NH2CH2CH2SO3H – NH2CH2CH2SO3K – H2O system exceeds the analogous values of YNHCH2SO3H – YNHCH2SO3K – H2O (Y = H, CH3, CH2CH2OH, C(CH3)3 and C2H5C6H5) systems. The obtained data on the buffer capacity of the aminoethanesulfonic acid – potassium aminoethanesulfonate – water system can be used in chemical analysis, microbiological and biochemical studies, and the acidity data of the solutions studied can simulate the chemisorption of acid gases (carbon and sulfur dioxides).

scholarly journals Grand-Reaction Method for Simulations of Ionization Equilibria and Ion Partitioning in a Broad Range of pH and Ionic Strength

2019 ◽  
Author(s):  
Jonas Landsgesell ◽  
Oleg Rud ◽  
Pascal Hebbeker ◽  
Raju Lunkad ◽  
Peter Košovan ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Reaction Method ◽  
Corrected Version ◽  
Major Flaw ◽  
Ion Partitioning ◽  
Original Manuscript ◽  
Ionization Equilibria

On 16th September 2019 we found a major flaw in the original manuscript, that has been uploaded to ChemRXiv. To prevent readers from implementing and using a flawed algorithm, we decided to replace the manuscript with this notice. We anticipate to upload a corrected version within few weeks.<br><br>

scholarly journals ELECTROMETRIC DETERMINATIONS OF THE DISSOCIATION OF GLYCOCOLL AND SIMPLE PEPTIDES1

1930 ◽  
Vol 14 (2) ◽  
pp. 255-275 ◽  
Author(s):  
Philip H. Mitchell ◽  
Jesse P. Greenstein
Keyword(s):  
Ionic Strength ◽  
Dissociation Constants ◽  
Hydrogen Ion ◽  
Carboxyl Groups ◽  
Relative Order ◽  
Specific Ion Effects ◽  
Ion Activity ◽  
Order Of Magnitude ◽  
Ion Effects ◽  
Basic Dissociation

1. The apparent acid and basic dissociation constants were determined potentiometrically by the methods of hydrolysis and of titration for the following ampholytes: Glycocoll, glycylglycocoll, alanylglycocoll, valylglycocoll, leucylglycocoll, methylleucylglycocoll, phenylalanylglycocoll and glycylglycylglycocoll. The constants were also determined in the presence of KCl and of K2SO4 at equal ionic strength. 2. In general, the relative order of magnitude of the constants decreased as the number of carbon atoms between amino and carboxyl groups increased. An explanation of this is offered on the basis of theories of electronic structure. 3. The application of the modern concepts of solutions to the case of the ampholytic ions is discussed. The inadequacy of the present theories is pointed out. 4. The constants were found, in general, to be functions of the hydrogen ion activity and the ionic strength of the solutions. Apparent contradictions to the Debye-Hückel theory are pointed out and partially explained on the basis of specific ion effects.

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