Mechanism of hydrolysis of aryl vinyl selenides. Selenium-stabilized carbonium ions

1980 ◽  
Vol 45 (1) ◽  
pp. 187-189 ◽  
Author(s):  
Robert A. McClelland ◽  
Michael Leung
Keyword(s):  
Carbonium Ions ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of

ChemInform Abstract: MECHANISM OF HYDROLYSIS OF ARYL VINYL SELENIDES. SELENIUM-STABILIZED CARBONIUM IONS

1980 ◽  
Vol 11 (25) ◽  
Author(s):  
R. A. MCCLELLAND ◽  
M. LEUNG
Keyword(s):  
Carbonium Ions ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of

scholarly journals Mechanism of Hydrolysis of Adenosinetriphosphate by Muscle Proteins and Its Relation to Muscular Contraction

1959 ◽  
Vol 234 (5) ◽  
pp. 1102-1107 ◽  
Author(s):  
Harvey M. Levy ◽  
D.E. Koshland
Keyword(s):  
Muscular Contraction ◽  
Muscle Proteins ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of

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

Micellar catalysis of organic reactions. VIII. Kinetic studies of the hydrolysis of 2-acetyloxybenzoic acid (aspirin) in the presence of micelles

1982 ◽  
Vol 35 (7) ◽  
pp. 1357 ◽  
Author(s):  
TJ Broxton
Keyword(s):  
Aqueous Solution ◽  
Cetyltrimethylammonium Bromide ◽  
Cetylpyridinium Chloride ◽  
Kinetic Studies ◽  
Base Catalysis ◽  
Plateau Region ◽  
General Base ◽  
Mechanism Of Hydrolysis ◽  
Ph Range ◽  
Hydrolysis Of

The hydrolysis of 2-acetyloxybenzoic acid in the pH range 6-12 has been studied in the presence of micelles of cetyltrimethylammonium bromide (ctab) and cetylpyridinium chloride (cpc). In the plateau region (pH 6-8) the hydrolysis is inhibited by the presence of micelles, while in the region where the normal BAC2 hydrolysis (pH > 9) occurs the reaction is catalysed by micelles of ctab and cpc. The mechanism of hydrolysis in the plateau region is shown to involve general base catalysis by the adjacent ionized carboxy group both in the presence and absence of micelles. This reaction is inhibited in the presence of micelles because the substrate molecules are solubilized into the micelle and water is less available in this environment than in normal aqueous solution.

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.

Human cholinesterases

2020 ◽  
pp. 63-120
Author(s):  
Sergey Varfolomeev ◽  
Bella Grigorenko ◽  
Sofya Lushchekina ◽  
Alexander Nemuchin
Keyword(s):  
Active Site ◽  
The Body ◽  
Polymorphic Modification ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Mechanism Of Hydrolysis ◽  
The Central Nervous System ◽  
The Stability ◽  
Hydrolysis Of ◽  
Enzyme Reactivity

The work is devoted to modeling the elementary stages of the hydrolysis reaction in the active site of enzymes belonging to the class of cholinesterases — acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The study allowed to describe at the molecular level the effect of the polymorphic modification of BChE, causing serious physiolog ical consequences. Cholinesterase plays a crucial role in the human body. AChE is one of the key enzymes of the central nervous system, and BChE performs protective functions in the body. According to the results of calculations using the combined method of quantum and molecular mechanics (KM/MM), the mechanism of the hydrolysis of the native acetylcholine substrate in the AChE active center was detailed. For a series of ester substrates, a method for estimation of dependence of the enzyme reactivity on the structure of the substrate has been developed. The mechanism of hydrolysis of the muscle relaxant of succininylcholine BChE and the effect of the Asp70Gly polymorph on it were studied. Using various computer simulation methods, the stability of the enzyme-substrate complex of two enzyme variants with succinylcholine was studied.

ChemInform Abstract: THE MECHANISM OF HYDROLYSIS OF A COBALT(III)-BOUND PHOSPHATE ESTER: TRANSPHOSPHORYLATION FROM OXYGEN TO NITROGEN

1981 ◽  
Vol 12 (11) ◽  
Author(s):  
J. MACB. HARROWFIELD ◽  
D. R. JONES ◽  
L. F. LINDOY ◽  
A. M. SARGESON
Keyword(s):  
Phosphate Ester ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of
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