Effects of immobilization on the kinetics of enzyme-catalyzed reactions. II. Urease in a packed-column differential reactor system

1976 ◽  
Vol 18 (5) ◽  
pp. 685-699 ◽  
Author(s):  
K. B. Ramachandran ◽  
D. D. Perlmutter
Keyword(s):  
Packed Column ◽  
Reactor System ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Kinetics Of

scholarly journals Thermodynamics and Kinetics of Glycolytic Reactions. Part I: Kinetic Modeling Based on Irreversible Thermodynamics and Validation by Calorimetry

2020 ◽  
Vol 21 (21) ◽  
pp. 8341
Author(s):  
Kristina Vogel ◽  
Thorsten Greinert ◽  
Monique Reichard ◽  
Christoph Held ◽  
Hauke Harms ◽  
...  
Keyword(s):  
Equilibrium State ◽  
Kinetic Models ◽  
Metabolic Pathways ◽  
Irreversible Thermodynamics ◽  
Titration Calorimetry ◽  
Metabolic Network Analysis ◽  
Arrhenius Relation ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Kinetics Of

In systems biology, material balances, kinetic models, and thermodynamic boundary conditions are increasingly used for metabolic network analysis. It is remarkable that the reversibility of enzyme-catalyzed reactions and the influence of cytosolic conditions are often neglected in kinetic models. In fact, enzyme-catalyzed reactions in numerous metabolic pathways such as in glycolysis are often reversible, i.e., they only proceed until an equilibrium state is reached and not until the substrate is completely consumed. Here, we propose the use of irreversible thermodynamics to describe the kinetic approximation to the equilibrium state in a consistent way with very few adjustable parameters. Using a flux-force approach allowed describing the influence of cytosolic conditions on the kinetics by only one single parameter. The approach was applied to reaction steps 2 and 9 of glycolysis (i.e., the phosphoglucose isomerase reaction from glucose 6-phosphate to fructose 6-phosphate and the enolase-catalyzed reaction from 2-phosphoglycerate to phosphoenolpyruvate and water). The temperature dependence of the kinetic parameter fulfills the Arrhenius relation and the derived activation energies are plausible. All the data obtained in this work were measured efficiently and accurately by means of isothermal titration calorimetry (ITC). The combination of calorimetric monitoring with simple flux-force relations has the potential for adequate consideration of cytosolic conditions in a simple manner.

Steady-State Kinetics of Enzyme Reactions in the Presence of Added Nucleophiles

1972 ◽  
Vol 50 (12) ◽  
pp. 1334-1359 ◽  
Author(s):  
Irwin Hinberg ◽  
Keith J. Laidler
Keyword(s):  
Specific Binding ◽  
Specific Binding Sites ◽  
Steady State Kinetics ◽  
Special Cases ◽  
Kinetics Of Formation ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Concentration Graphs ◽  
Kinetics Of ◽  
Hydrolysis Of

Many enzyme-catalyzed reactions, such as hydrolyses, give rise to two products P1 and P2 which are formed in different reaction steps. The second product P2 is frequently formed by hydrolysis of an intermediate such as an acyl-enzyme or a phosphoryl-enzyme. An alternative nucleophile N introduced into the system forms an additional product P3. The present paper is concerned with the kinetics of formation of P1, P2, and P3 in the presence of added nucleophiles. A number of alternative mechanisms are considered, and equations are derived for the rates of formation of the three products, and the Michaelis constant, as functions of nucleophile concentration. Graphs are presented showing the variations of these parameters with the concentration of N, for a variety of special cases. Special attention is given to the possibility of specific binding sites for the water and the nucleophile molecules.The data for a number of enzyme systems are discussed with reference to the treatment. For reactions catalyzed by alkaline phosphatase it is concluded that only one mechanism (mechanism VI) is consistent with the results.

scholarly journals KINETICS OF LYSIS BY CLOSTRIDIUM SEPTICUM HEMOLYSIN

1944 ◽  
Vol 80 (4) ◽  
pp. 333-339 ◽  
Author(s):  
Alan W. Bernheimer
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Clostridium Septicum ◽  
Ph Optimum ◽  
Hydrogen Ion Concentration ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Kinetics Of

The kinetics of the hemolytic reaction effected by the hemolysin of Clostridium septicum, strain 44, has been studied with regard to the effect of concentration, temperature, and hydrogen ion concentration on the rate of the hemolytic reaction. The kinetics of hemolysis was found to resemble in several respects that of enzyme-catalyzed reactions, but differed in the absence of a clearly defined pH optimum. Attention is drawn to differences between the hemolytic system studied and certain other hemolytic systems.

Levitated Drop Microreactors for Biochemical Kinetics

2012 ◽  
Vol 560-561 ◽  
pp. 395-400
Author(s):  
Alexander Scheeline ◽  
Woo Hyuck Choi ◽  
Edward T. Chainani ◽  
Khan T. Ngo
Keyword(s):  
Free Radicals ◽  
Chemical Analysis ◽  
Sample Preparation ◽  
Chemical Processes ◽  
Materials Processing ◽  
Biochemical Reactions ◽  
Biochemical Kinetics ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Kinetics Of

Ultrasonically-levitated drops have been widely studied for materials processing and for sample preparation for chemical analysis. We report on the development of such drops for study of kinetics of enzyme-catalyzed reactions and other chemical processes. We review how to simply and reliably levitate drops, discuss why such drops are desirable for studying biochemical reactions, especially those generating or consuming free radicals, and report progress towards routine kinetics measurements in microliter drops.

scholarly journals Compare and contrast the reaction coordinate diagrams for chemical reactions and cytoskeletal force generators

2013 ◽  
Vol 24 (4) ◽  
pp. 433-439 ◽  
Author(s):  
Jonathan M. Scholey
Keyword(s):  
Intracellular Transport ◽  
Molecular Mechanisms ◽  
Equilibrium Constants ◽  
Reaction Coordinate ◽  
Simple Chemical ◽  
Interdisciplinary Framework ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Compare And Contrast ◽  
Kinetics Of

Reaction coordinate diagrams are used to relate the free energy changes that occur during the progress of chemical processes to the rate and equilibrium constants of the process. Here I briefly review the application of these diagrams to the thermodynamics and kinetics of the generation of force and motion by cytoskeletal motors and polymer ratchets as they mediate intracellular transport, organelle dynamics, cell locomotion, and cell division. To provide a familiar biochemical context for discussing these subcellular force generators, I first review the application of reaction coordinate diagrams to the mechanisms of simple chemical and enzyme-catalyzed reactions. My description of reaction coordinate diagrams of motors and polymer ratchets is simplified relative to the rigorous biophysical treatment found in many of the references that I use and cite, but I hope that the essay provides a valuable qualitative representation of the physical chemical parameters that underlie the generation of force and motility at molecular scales. In any case, I have found that this approach represents a useful interdisciplinary framework for understanding, researching, and teaching the basic molecular mechanisms by which motors contribute to fundamental cell biological processes.

Reversal in the kinetics of the M state decay of D96N bacteriorhodopsin: probing of enzyme catalyzed reactions

1996 ◽  
Vol 36 (1-3) ◽  
pp. 470-474 ◽  
Author(s):  
P.C. Pandey ◽  
Sudha Singh ◽  
Bipin Upadhyay ◽  
Howard H. Weetall ◽  
Peter K. Chen
Keyword(s):  
State Decay ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Kinetics Of
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