scholarly journals Kinetics and Mechanism of Hydrolysis of Acetylthiocholine by Butyrylcholine Esterase

2002 ◽  
Vol 57 (11-12) ◽  
pp. 1072-1077 ◽  
Author(s):  
Karel Komers ◽  
Alexandr Čegan ◽  
Marek Link
Keyword(s):  
Acetic Acid ◽  
Kinetics And Mechanism ◽  
Kinetics Parameters ◽  
Mechanism Of Hydrolysis ◽  
Ph Stat ◽  
Stat Method ◽  
Ellman’S Method ◽  
Hydrolysis Of

Kinetics and mechanism of hydrolysis of acetylthiocholine by the enzyme butyrylcholine esterase was studied. The spectrophotometric Ellman’s method and potentiometric pH-stat method were used for continuous determination of the actual concentration of the products thiocholine and acetic acid in the reaction mixture. The validity of the Michaelis-Menten (Briggs-Haldane) equation in the whole course of the reaction under used conditions was proved. The corresponding kinetics parameters (Vm and KM) were calculated from the obtained dependences of concentration of thiocholine or acetic acid vs. time and compared. From this comparison the deciding kinetic role of the step producing thiocholine was derived. The values of initial molar concentration of the enzyme and of the rate constants of the kinetic model were estimated.

scholarly journals Neptunium(iv)-hydroxamate complexes: their speciation, and kinetics and mechanism of hydrolysis

2019 ◽  
Vol 48 (2) ◽  
pp. 673-687 ◽  
Author(s):  
S. Edwards ◽  
F. Andrieux ◽  
C. Boxall ◽  
M. J. Sarsfield ◽  
R. J. Taylor ◽  
...  
Keyword(s):  
Kinetics And Mechanism ◽  
Nuclear Reprocessing ◽  
Mechanism Of Hydrolysis ◽  
Time Determination ◽  
First Time ◽  
Hydrolysis Of

First time determination of rate parameters for hydrolysis of mono- and bis-acetohydroxamatoneptunium(iv) complexes under conditions relevant to nuclear reprocessing.

The Kinetics and Mechanism of Hydrolysis of Tetrachloroaurate(III)

1966 ◽  
Vol 5 (11) ◽  
pp. 1943-1946 ◽  
Author(s):  
Franklin H. Fry ◽  
Gordon A. Hamilton ◽  
John Turkevich
Keyword(s):  
Kinetics And Mechanism ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of

Commercial Dental Composite: Determination of Reaction Advancement and Study of the Migration of Organic Compounds

2005 ◽  
Vol 13 (3) ◽  
pp. 223-234
Author(s):  
C. Sanglar ◽  
M. Defay ◽  
H. Waton ◽  
A. Bonhomme ◽  
S. Alamercery ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
Aqueous Media ◽  
Dental Composite ◽  
Dental Composites ◽  
Hydrophilic Monomer ◽  
Methacrylate Monomers ◽  
Urethane Dimethacrylate ◽  
Hydrolysis Of

This work on organic dental composites was undertaken to determine the role of residual reactive methacrylate functions at the end of the photopolymerization cycle, and to investigate the fate of the residual monomers and oligomers in organic (ethanol) and aqueous (water and artificial saliva) media. The results show that all the methacrylate monomers present in dentine migrate into ethanol (about 1% (w/w)). In aqueous media on the other hand, only the most hydrophilic monomer (UDMA) migrates (0.05% (w/w)) into water and 0.03% into artificial saliva (pH = 9). This desorption in the three media is accompanied by the hydrolysis of monomers, leading to the formation of monohydrolyzed urethane dimethacrylate (UDMA) and bis-phenyl glycidyl dimethacrylate (BISGMA); UDMA and BISGMA are completely hydrolyzed in artificial saliva. The alkalinity of the milieu apparently favours the hydrolysis of methacrylate functions.

Determination of Carbaryl Residues in Honey Bees

1965 ◽  
Vol 48 (4) ◽  
pp. 771-774
Author(s):  
D P Johnson ◽  
H A Stansbury
Keyword(s):  
Aqueous Solution ◽  
Acetic Acid ◽  
Quantitative Determination ◽  
Honey Bees ◽  
Methylene Chloride ◽  
Hydrolysis Product ◽  
Separate Analysis ◽  
Yellow Substance ◽  
Hydrolysis Of

Abstract A method has been developed for detecting residues of carbaryl (1-naphthyl methylcarbamate) as well as its hydrolysis product, 1-naphthol, in dead bees. The method is based on extraction of the bees with benzene, followed by a cleanup involving liquid partitioning and chromatography on Florisil. The quantitative determination involves hydrolysis of carbaryl to 1-naphthol and coupling of the latter with p-nitrobenzenediazonium fluoborate in acetic acid to form a yellow substance. For separate analysis, free 1-naphthol is separated from methylene chloride into a basic aqueous solution. The sensitivity of the method is about 0.1 ppm; recoveries averaged 85.6 ± 6.6% for 1- naphthol and 83.8 ± 2.7% for carbaryl.

Hydrolysis of Zirconium Propoxide by an Esterification Reaction

1992 ◽  
Vol 271 ◽  
Author(s):  
I. Laaziz ◽  
A. Larbot ◽  
C. Guizard ◽  
A. Julbe ◽  
L. Cot
Keyword(s):  
Acetic Acid ◽  
Light Scattering ◽  
Crystalline Structure ◽  
Structure Determination ◽  
Nmr Spectra ◽  
Esterification Reaction ◽  
Zirconium Propoxide ◽  
Size Growth ◽  
Hydrolysis Of

ABSTRACTZirconium propoxide hydrolysis was performed with the help of an esterification reaction using acetic acid. Products, obtained according to the value of hydrolysis ratio, are successively crystals, sols and gels or precipitates. The similarity of FUR and NMR spectra for crystals and gels allows to think that the arrangements of ligands around the zirconium atoms are close. The crystalline structure determination permits to precise the environment : acetate groups are always bridging and propoxy groups can be bridging or terminal. Clusters containing 9 zirconium atoms, bridged by oxygen atoms, exist in the structure. The colloid size growth was performed by light scattering. A discussion of the role of acetic acid and the competition between the possible reactions is given.

ChemInform Abstract: KINETICS AND MECHANISM OF HYDROLYSIS OF CHLORO-1,3,5-TRIAZINES. ATRAZINE

1982 ◽  
Vol 13 (4) ◽  
Author(s):  
S. J. PLUST ◽  
J. R. LOEHE ◽  
F. J. FEHER ◽  
J. H. BENEDICT ◽  
H. F. HERBRANDSON
Keyword(s):  
Kinetics And Mechanism ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of

ChemInform Abstract: KINETICS AND MECHANISM OF HYDROLYSIS OF 4-PHENYLALLOPHANATES

1984 ◽  
Vol 15 (42) ◽  
Author(s):  
M. M. AL SABBAGH ◽  
M. CALMON ◽  
J.-P. CALMON
Keyword(s):  
Kinetics And Mechanism ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of

Kinetics and mechanism of hydrolysis of 4-phenylallophanates

1984 ◽  
pp. 1233 ◽  
Author(s):  
Mohamed Mowafak Al Sabbagh ◽  
Michelle Calmon ◽  
Jean-Pierre Calmon
Keyword(s):  
Kinetics And Mechanism ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of
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