scholarly journals Kinetic analysis of the control through inhibition of autocatalytic zymogen activation

1992 ◽  
Vol 282 (2) ◽  
pp. 583-587 ◽  
Author(s):  
M C Manjabacas ◽  
E Valero ◽  
M García-Moreno ◽  
F García-Cánovas ◽  
J N Rodríguez ◽  
...  
Keyword(s):  
Steady State ◽  
Kinetic Analysis ◽  
Kinetic Equations ◽  
Enzyme Regulation ◽  
Activation Process ◽  
Transient Phase ◽  
Zymogen Activation ◽  
Irreversible Inhibitor ◽  
The One ◽  
The Complement System

A global kinetic analysis of a model of an autocatalytic zymogen-activation process in which an irreversible inhibitor competes with the zymogen for the active site of the proteinase is presented. Processes like the one here described are of great physiological interest because they are involved in the enzyme regulation of the gastrointestinal-tract enzymes, in blood coagulation, in fibrinolysis and in the complement system. The kinetic equations of both the transient phase and the steady state are derived for this mechanism. In addition, we have introduced a new parameter related to the kinetic behaviour of the system which allows us to predict whether the inhibition route or the activation route prevails in the steady state of the system. Finally, we extend the kinetic equations derived to different particular cases of the system studied.

scholarly journals Kinetic behaviour of zymogen activation processes in the presence of an inhibitor

1993 ◽  
Vol 290 (2) ◽  
pp. 463-470 ◽  
Author(s):  
R Varón ◽  
M C Manjabacas ◽  
M García-Moreno ◽  
E Valero ◽  
F Garcia-Canovas
Keyword(s):  
Data Analysis ◽  
Kinetic Analysis ◽  
General Model ◽  
Kinetic Data ◽  
Kinetic Equations ◽  
Zymogen Activation ◽  
Activation Model ◽  
Kinetic Behaviour ◽  
Irreversible Inhibition

A global kinetic analysis of a general zymogen activation model, where not only the activating but also the activated enzyme suffer an irreversible inhibition is presented. A reaction in which the enzyme acts upon a substrate is coupled to monitor the process. In addition, we determined the corresponding kinetic equations for a number of particular cases of the general model studied. Finally, a kinetic data analysis and a procedure to discriminate among the different mechanisms considered, which are based on the kinetic equations obtained, are suggested.

scholarly journals Kinetic analysis of the transient phase and steady state of open multicyclic enzyme cascades.

2005 ◽  
Vol 52 (4) ◽  
pp. 765-780 ◽  
Author(s):  
Ramón Varón ◽  
Bent H Havsteen ◽  
Edelmira Valero ◽  
Milagros Molina-Alarcón ◽  
Francisco García-Cánovas ◽  
...  
Keyword(s):  
Steady State ◽  
Data Analysis ◽  
Kinetic Analysis ◽  
Kinetic Data ◽  
Time Course ◽  
Intrinsic Value ◽  
Transient Phase ◽  
Enzyme Cascade ◽  
Rapid Equilibrium ◽  
Enzyme Cascades

This paper presents a kinetic analysis of the whole reaction course, i.e. of both the transient phase and the steady state, of open multicyclic enzyme cascade systems. Equations for fractional modifications are obtained which are valid for the whole reaction course. The steady state expressions for the fractional modifications were derived from the latter equations since they are not restricted to the condition of rapid equilibrium. Finally, the validity of our results is discussed and tested by numerical integration. Apart from the intrinsic value of knowing the kinetic behaviour of any of the species involved in any open multicyclic enzyme cascade, the kinetic analysis presented here can be the basis of future contributions concerning open multicyclic enzyme cascades which require the knowledge of their time course equations (e.g. evaluation of the time needed to reach the steady state, suggestion of kinetic data analysis, etc.), analogous to those already carried out for open bicyclic cascades.

scholarly journals Computer program for the kinetic equations of enzyme reactions. The case in which more than one enzyme species is present at the onset of the reaction

1991 ◽  
Vol 278 (1) ◽  
pp. 91-97 ◽  
Author(s):  
R Varón ◽  
B H Havsteen ◽  
M García ◽  
F García-Canóvas ◽  
J Tudela
Keyword(s):  
Steady State ◽  
Computer Program ◽  
Enzyme System ◽  
Kinetic Equations ◽  
British Library ◽  
Transient Phase ◽  
Enzyme Reactions ◽  
Steady State Kinetic ◽  
State Kinetic ◽  
Enzyme Species

This paper presents an extension of the program developed by Varón, Havsteen, García, García-Cánovas & Tudela [(1990) Biochem. J. 270, 825-828] for the expression of the transient-phase and steady-state kinetic equations of a general enzyme system in which the only enzyme species present at the onset of the reaction is the free enzyme. The program has been extended to situations in which more than one enzyme species may be present at the onset of the reaction. The program is given in Supplementary Publication SUP50165 (5 pages), which has been deposited at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1991) 273, 5.

Tyrosinase: kinetic analysis of the transient phase and the steady state

1994 ◽  
Vol 1204 (1) ◽  
pp. 33-42 ◽  
Author(s):  
JoséRamón Ros ◽  
JoséNeptuno Rodríguez-López ◽  
Francisco García-Cánovas
Keyword(s):  
Steady State ◽  
Kinetic Analysis ◽  
Transient Phase

scholarly journals The steady-state kinetics of isotope exchange for one substrate–one product enzymic reactions

1973 ◽  
Vol 135 (4) ◽  
pp. 861-866 ◽  
Author(s):  
Ivan G. Darvey
Keyword(s):  
Steady State ◽  
Isotope Exchange ◽  
Kinetic Equations ◽  
Enzyme Reaction ◽  
Radioactive Material ◽  
First Order ◽  
Steady State Kinetics ◽  
The One ◽  
Allosteric Mechanisms ◽  
Kinetics Of

Steady-state kinetic equations for isotope exchange are derived for a number of one substrate–one product enzymic mechanisms in which two molecules of substrate or product can be combined with an enzyme molecule at the one time (e.g. allosteric mechanisms). The usual assumption, that the radioactive material is distributed among the substrate and product components according to a first-order law, is not valid. One can recognize whether isotope-exchange kinetics of an enzyme reaction follows first-order behaviour by using various initial concentrations of the labelled substance added to a mixture.

scholarly journals Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1686
Author(s):  
Andrey Galukhin ◽  
Roman Nosov ◽  
Ilya Nikolaev ◽  
Elena Melnikova ◽  
Daut Islamov ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Single Step ◽  
Polymerization Kinetics ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Diffusion Controlled ◽  
Polymerization Product ◽  
The One ◽  
Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

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