scholarly journals A new method for the determination of the amidase activity of trypsin: kinetics of the hydrolysis of benzoyl-l-arginineamide

1955 ◽  
Vol 59 (3) ◽  
pp. 506-509 ◽  
Author(s):  
S. A. Bernhard
Keyword(s):  
New Method ◽  
Amidase Activity ◽  
Kinetics Of ◽  
Hydrolysis Of

scholarly journals The linkage between binding of the C-terminal domain of hirudin and amidase activity in human α-thrombin

1993 ◽  
Vol 289 (2) ◽  
pp. 475-480 ◽  
Author(s):  
R de Cristofaro ◽  
B Rocca ◽  
B Bizzi ◽  
R Landolfi
Keyword(s):  
Rate Constants ◽  
Binding Constant ◽  
Amidase Activity ◽  
Equilibrium Binding ◽  
Viscosity Effects ◽  
The Individual ◽  
Individual Rate ◽  
Hydrolysis Of ◽  
Equilibrium Binding Constant

A method derived from the analysis of viscosity effects on the hydrolysis of the amide substrates D-phenylalanylpipecolyl-arginine-p-nitroaniline, tosylglycylprolylarginine-p-nitroanaline and cyclohexylglycylalanylarginine-p-nitroalanine by human alpha-thrombin was developed to dissect the Michaelis-Menten parameters Km and kcat into the individual rate constants of the binding, acylation and deacylation reactions. This method was used to analyse the effect of the C-terminal hirudin (residues 54-65) [hir-(54-65)] domain on the binding and hydrolysis of the three substrates. The results showed that the C-terminal hir-(54-65) fragment affects only the acylation rate, which is increased approx. 1.2-fold for all the substrates. Analysis of the dependence of acylation rate constants on hirudin-fragment concentration, allowed the determination of the equilibrium binding constant of C-terminal hir-(54-65) (Kd approximately 0.7 microM). In addition this peptide was found to competitively inhibit thrombin-fibrinogen interaction with a Ki which is in excellent agreement with the equilibrium constant derived from viscosity experiments. These results demonstrate that binding of hir-(54-65) to the fibrinogen recognition site of thrombin does not affect the equilibrium binding of amide substrates, but induces only a small increase in the acylation rate of the hydrolysis reaction.

scholarly journals Kinetika Reaksi Hidrolisis Pati Biji Alpukat (Persea americana Mill) dengan Katalis HCl

2020 ◽  
Vol 4 (1) ◽  
pp. 120-131
Author(s):  
Sitti Rahmawati ◽  
Asnila Asnila ◽  
Suherman Suherman ◽  
Paulus Hengky Abram
Keyword(s):  
Reaction Order ◽  
Second Order ◽  
Hydrolysis Reaction ◽  
Starch Hydrolysis ◽  
First Order ◽  
Graph Method ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Avocado Seed

One of the plants that can be used as raw material for making sugar is plants that contain starch content such as avocado seeds. This study aims to determine the reaction order, the reaction rate constant from the hydrolysis of avocado seed starch using HCl. The method of this research is to determine the optimum concentration of HCl hydrolysis reaction from avocado seed starch using various concentrations of HCl (0.5 M; 1 M; 1.5 M; 2 M; 2.5 M) at the optimum temperature and stirring time (90oC for 70 minute). The hydrolysis process was followed by neutralization using 5 M NaOH solution and evaporated to obtain concentrated glucose, glucose was analyzed qualitatively and quantitatively by the Benedict method and the phenol sulfuric acid method. Based on the results of the maximum glucose levels obtained from the hydrolysis of variations in the concentration of HCl avocado seed starch, HCl 1.5 M. Furthermore, determine the kinetics of the starch hydrolysis reaction using time variations (30, 40, 50, 60 and 70) minutes at 90oC and concentrations The HCl 1.5 M. reaction order is determined by the intral method and the graph method. Determination of the first order graph method is done by plotting the value of ln [A] versus time, while the second order by plotting the value of 1 / [A] versus time. The first order with a 93% confidence level was obtained from the value of R2 = 0.9312, while the second order was 85% obtained from the value of R2 = 0.8581. Determination of the order of the integral method k value tends to remain in the first order formula with an average of k = 0.01962 minutes-1. Based on the two methods, it can be determined that the kinetics of the avocado seed starch hydrolysis reaction follows a first-order reaction.

Etude de la coagulation des eaux par fluorométrie

1975 ◽  
Vol 2 (3) ◽  
pp. 253-261
Author(s):  
Jean-B. Sérodes ◽  
Alain Soucy
Keyword(s):  
Water Treatment ◽  
Low Temperatures ◽  
New Method ◽  
Fluorometric Method ◽  
Aluminum Salts ◽  
Aluminum Ion ◽  
Water Treatment Plants ◽  
Residual Aluminum ◽  
Hydrolysis Of

The use of a fluorometric method for the determination of residual aluminum salts used as coagulants in water treatment has permitted evaluation of the influence of some factors, particularly temperature, on the hydrolysis of these salts. The yield of hydrolysis is lessened by low temperatures and aluminum ion is more sensitive than aluminate ion. This new method is suggested for detecting abnormal working of water treatment plants.

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