Double mixing stopped-flow method for the study of equilibria and kinetics of dimer-tetramer association of hemoglobins: Studies on Hb Carp, Hb A, and Hb Rothschild

The kinetics of bromination of the 1,2-dihydro-1,3-dimethyl-2-oxopyrimidinium cation (Q+) in aqueous media (pH 0–5) have been studied using the stopped-flow method. At the higher acidities (pH < 2) the results are consistent with rate determining attack by bromine upon the pseudobase (QOH), whereas at low acidities (pH > 4) it appears that pseudobase formation is rate determining. The change occurs because at high acidity the reversal of the pseudobase QOH to the cation is fast relative to bromine attack, whereas at low acidity the converse is true. Results obtained at intermediate acidities (pH 2–4) are consistent with this interpretation.A separate kinetic study of pseudobase formation (and decomposition) yielded rate constants in good agreement with those derived from the bromination study.

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Etude cinétique des systèmes Cu(II)•Adénosine et Cu(II)•D-Ribose

Canadian Journal of Chemistry ◽

10.1139/v72-499 ◽

1972 ◽

Vol 50 (19) ◽

pp. 3117-3123 ◽

Cited By ~ 1

Author(s):

G. Boivin ◽

M. Zador

Keyword(s):

Kinetic Parameters ◽

Acidic Medium ◽

Temperature Jump ◽

Strong Acid ◽

Basic Medium ◽

Stopped Flow ◽

Acid Solutions ◽

Flow Method ◽

Kinetics Of ◽

Adenine Base

The kinetics of the formation and dissociation of Cu(II) complexes of adenosine have been determined in acidic and basic medium. In acidic medium, the complex is formed between the Cu(II) and the adenine base and the kinetic parameters have been obtained in this case using a temperature jump method. In basic medium, only the dissociation of the complexes could be studied by a stopped-flow method, by addition of EDTA or strong acid solutions. In these complexes, Cu(II) is bridged with ribose hydroxyls. Finally, D-ribose has also been studied for comparison in the same conditions. The mechanism of these reactions is discussed.

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The Adsorption-Desorption Kinetics of Dodecyl Sulfate Ions to and from Polystyrene Latex Using the Electric Conductivity Stopped-flow Method.

NIPPON KAGAKU KAISHI ◽

10.1246/nikkashi.1998.167 ◽

1998 ◽

pp. 167-173

Author(s):

Shiori MIYAMOTO

Keyword(s):

Electric Conductivity ◽

Polystyrene Latex ◽

Desorption Kinetics ◽

Stopped Flow ◽

Sulfate Ions ◽

Flow Method ◽

Dodecyl Sulfate ◽

Adsorption Desorption ◽

Kinetics Of

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Kinetics of the Reversible Transformation of 2,3-Dioxogulonic Acid into its Enol as a Function of the pH of the Medium

Zeitschrift für Naturforschung A ◽

10.1515/zna-1978-1011 ◽

1978 ◽

Vol 33 (10) ◽

pp. 1184-1189

Author(s):

J. Zuluaga ◽

P. Martínez

Keyword(s):

Kinetic Study ◽

Equilibrium Constant ◽

Rate Constants ◽

Disodium Salt ◽

Stopped Flow ◽

Free Energies ◽

Reversible Transformation ◽

Flow Method ◽

Kinetic Coefficients ◽

Kinetics Of

Abstract 2,3-dioxogulonic acid and the disodium salt of its enol were synthesised, isolated and identified both chemically and spectroscopically. A kinetic study was carried out on its equilibrium by means of the “stopped flow” method for rapid processes, and the rate constants for the forward and backward reaction were determined as a function of the pH of the medium. The kinetic coefficients involved, equilibrium constant and Gibbs free energies were also determined.

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Etude du système acridine orange – poly(C) et de son interaction avec les complexes du palladium(II)

Canadian Journal of Chemistry ◽

10.1139/v84-288 ◽

1984 ◽

Vol 62 (9) ◽

pp. 1681-1686 ◽

Cited By ~ 2

Author(s):

Robert Ménard ◽

Miklos Zador

Keyword(s):

Acridine Orange ◽

Thermodynamic Parameters ◽

Rate Constant ◽

Kinetic Studies ◽

Stopped Flow ◽

Flow Method ◽

Polycytidylic Acid ◽

Low Concentrations ◽

C Complex ◽

Kinetics Of

The complex formed between acridine orange (AO) and polycytidylic acid (poly(C)) was studied by spectrophotometry and spectrofluorometry. The complex was characterized by its stoichiometry, structure, and the thermodynamic parameters of its formation. The results are in agreement with an external aggregation of the protonated dye along the negatively charged poly(C) chain and indicate that approximately two AO molecules are bound per nucleotide unit of poly(C). The kinetics of the reaction between this complex and a Pd(II) complex was studied by the stopped-flow method. The addition of (dien)Pd(II) to the AO–poly(C) complex leads to the dissociation of the latter, due to fixation of the Pd(II) complex to the N3 site of the cytosine base of poly(C). The rate constant for the AO liberation, extrapolated at zero AO concentration, corresponds to the rate constant of Pd(II) fixation on poly(C). This indicates that AO can be used as an indicator for this reaction and allows kinetic studies at very low concentrations (≤ 5 × 10−6 M).

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Stopped-Flow Spectrophotometric Studies of the Kinetics of Interaction of Dihydroxyfumaric Acid with the DPPH Free Radical

Chemistry Journal of Moldova ◽

10.19261/cjm.2010.05(2).11 ◽

2010 ◽

Vol 5 (2) ◽

pp. 83-87

Author(s):

Natalia Secara

Keyword(s):

Free Radical ◽

Reaction Kinetics ◽

Rate Constant ◽

Stopped Flow ◽

Flow Method ◽

Reaction Proceeds ◽

Reaction Orders ◽

Stoichiometric Reaction ◽

Two Stages ◽

Kinetics Of

The reaction of dihydroxyfumaric acid with the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was studied using the stopped-flow method, in order to describe the reaction kinetics. Dihydroxyfumaric acid reacts very rapidly with DPPH, the reaction being completed in several minutes. This 2-stoichiometric reaction proceeds in two stages, with reaction orders of 1 and 0.76 with respect to DPPH, and 0.5 and 0.3 with respect to DHF, respectively. The rate constant of the two stages of the reaction were found to be 39.1 (L/mol•s) and 0.0012 (s-1) at 20º C and pH 4.0.

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The kinetics of partial processes in the oxidation of ascorbic acid catalyzed by vanadyl tetrasulphophthalocyanine

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19820744 ◽

1982 ◽

Vol 47 (3) ◽

pp. 744-754 ◽

Cited By ~ 5

Author(s):

Dana M. Wagnerová ◽

Jaroslav Votruba ◽

Jürgen Blanck ◽

Josef Vepřek-Šiška

Keyword(s):

Experimental Data ◽

Ascorbic Acid ◽

Reaction Mechanism ◽

Rate Constants ◽

Stopped Flow ◽

Adaptive Identification ◽

Flow Method ◽

Acid Catalyzed ◽

Kinetics Of

The rapid partial reactions of the oxidation of ascorbic acid by dioxygen with vanadyl tetrasulphophthalocyanine as a catalyst were studied by the stopped-flow method. The experimental data were treated on a computer and compared with the kinetic implications resulting from the proposed mechanism. Application of the adaptive identification method led to quantitative solution of the mechanism, i.e. determination of the values of all the isolated rate constants of the reaction mechanism.

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The kinetics of the reactions of boric acid with 5-substituted salicylate ions

Canadian Journal of Chemistry ◽

10.1139/v79-151 ◽

1979 ◽

Vol 57 (8) ◽

pp. 920-923 ◽

Cited By ~ 2

Author(s):

Alan Queen ◽

Lorne Davies ◽

Andrew Con

Keyword(s):

Boric Acid ◽

Stability Constants ◽

Arrhenius Equation ◽

Equilibrium Temperature ◽

Stopped Flow ◽

Flow Method ◽

Kinetics Of ◽

Absorption Measurements

Salicylate ions form 1:1 complexes with boric acid. The kinetics of these reactions have been studied by the stopped-flow method and stability constants have been calculated from absorption measurements on the solutions at equilibrium. Temperature studies of the rates of reaction of boric acid and unsubstituted salicylate ions at pH 5.29 have been carried out. The data correlate well with the Arrhenius equation.

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