pH-stat methodology in continuous monitoring of the kinetics of hydrolysis of phosphate esters catalysed by alkaline phosphatase from human placenta: Limitations, advantages and theoretical aspects

1991 ◽  
Vol 24 (1) ◽  
pp. 45-58 ◽  
Author(s):  
M. G. Roig ◽  
M. A. Serrano ◽  
J. F. Bello ◽  
J. M. Cachaza ◽  
J. F. Kennedy
Keyword(s):  
Alkaline Phosphatase ◽  
Human Placenta ◽  
Continuous Monitoring ◽  
Phosphate Esters ◽  
Kinetics Of Hydrolysis ◽  
Ph Stat ◽  
Kinetics Of ◽  
Hydrolysis Of

Two New Methods Monitoring Kinetics of Hydrolysis of Acetylcholine and Acetylthiocholine

2005 ◽  
Vol 60 (11-12) ◽  
pp. 943-946 ◽  
Author(s):  
Šárka Štěpánková ◽  
Martina Vránová ◽  
Pavla Zdražilová ◽  
Karel Komers ◽  
Alena Komersová ◽  
...  
Keyword(s):  
Hplc Method ◽  
Advantages And Disadvantages ◽  
New Methods ◽  
Kinetics Of Hydrolysis ◽  
Primary Products ◽  
Ph Stat ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
In Vitro Kinetics

Hydroxylamine and HPLC methods, measuring in vitro kinetics of enzymatic hydrolysis of acetylcholine or acetylthiocholine by cholinesterases, are described. The hydroxylamine method determines the dependence of substrate concentration vs. time, the HPLC method is able to measure simultaneously the time dependences of substrate and both primary products, choline or thiocholine, and acetic acid. Practical determinations are shown, comparison with known (above all Ellman’s and pH-stat) methods, advantages and disadvantages are discussed.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

Kinetics of Hydrolysis of Some Bifunctional Schiff Bases

1990 ◽  
Vol 37 (5) ◽  
pp. 479-487 ◽  
Author(s):  
M.R. Mahmoud ◽  
A.M. El-Nady ◽  
F.A. Adam ◽  
M.A. El-Taher
Keyword(s):  
Schiff Bases ◽  
Kinetics Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

scholarly journals Isothermal and non-isothermal kinetics of hydrolysis of 1-[2-(2- pentyloxyphenylcarbamoyloxy)-(2-methoxymethyl)-ethyl]- perhydroazepinium chloride (BK 129)

2013 ◽  
Vol 60 (2) ◽  
pp. 43-48
Author(s):  
Stankovičová M. ◽  
Bezáková Ž. ◽  
Beňo P. ◽  
Húšťavová P.
Keyword(s):  
Biological Activity ◽  
Alkaline Hydrolysis ◽  
Functional Group ◽  
Isothermal Kinetics ◽  
Basic Part ◽  
Buffer Solutions ◽  
Kinetics Of Hydrolysis ◽  
Short Time ◽  
Kinetics Of ◽  
Hydrolysis Of

Abstract The substance BK 129 - 1-[2-(2-pentyloxyphenylcarbamoyloxy)-(2-methoxymethyl)-ethyl]-perhydroazepinium chloride was prepared in terms of influence of the connecting chain between the carbamate functional group and the basic part of molecule on biological activity. Such a structural feature is important with regard to its stability. In this work we determined the rate constants of alkaline hydrolysis of this compound at increased temperature under isothermal and non-isothermal conditions. The hydrolysis was also performed in buffer solutions with the purpose of evaluating its stability. Non-isothermal tests of stability enable to reduce the number of analyses. The necessary data for stability of compound are in this way achieved in a short time.

scholarly journals Chicken Intestinal Alkaline Phosphatase

1960 ◽  
Vol 43 (6) ◽  
pp. 1149-1169 ◽  
Author(s):  
M. Kunitz
Keyword(s):  
Alkaline Phosphatase ◽  
Zinc Ions ◽  
Magnesium Ions ◽  
Intestinal Alkaline Phosphatase ◽  
Reversible Inactivation ◽  
Higher Temperature ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Zn Ions ◽  
Denaturation Of Proteins

Purified chicken intestinal alkaline phosphatase is active at pH 8 to 9, but becomes rapidly inactivated with change of pH to 6 or less. Also, a solution of the inactivated enzyme at pH 4.5 rapidly regains its activity at pH 8. In the range of pH 6 to 8 a solution of purified alkaline phosphatase consists of a mixture of active and inactive enzyme in equilibrium with each other. The rate of inactivation at lower pH and of reactivation at higher pH increases with increase in temperature. Also, the activity at equilibrium in the range of pH 6 to 8 increases with temperature so that a solution equilibrated at higher temperature loses part of its activity on cooling, and vice versa, a rise in temperature shifts the equilibrium toward higher activity. The kinetics of inactivation of the enzyme at lower pH and the reactivation at higher pH is that of a unimolecular reaction. The thermodynamic values for the heat and entropy of the reversible inactivation and reactivation of the enzyme are considerably lower than those observed for the reversible denaturation of proteins. The inactivated enzyme at pH 4 to 6 is rapidly reactivated on addition of Zn ions even at pH 4 to 6. However, zinc ions are unable to replace magnesium ions as cocatalysts for the enzymatic hydrolysis of organic phosphates by alkaline phosphatase.

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