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Updated: Jun 9, 2026
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Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Dynamic disorder in quasi-equilibrium enzymatic systems
Srabanti Chaudhury1, Oleg A Igoshin
1Department of Bioengineering, Rice University, Houston, Texas, United States of America.
Plos One
|September 3, 2010
Summary
Enzyme conformational fluctuations do not alter catalytic rates in the quasi-equilibrium limit. Macroscopic rate laws, like Michaelis-Menten, remain valid even with slow enzyme dynamics.
Area of Science:
- Biochemistry
- Chemical Kinetics
- Enzyme Kinetics
Background:
- Enzyme catalytic rates and conformations fluctuate dynamically.
- Macroscopic rate laws, such as the Michaelis-Menten law, can describe some enzyme behaviors.
- Understanding enzyme dynamics is crucial for predicting their function.
Purpose of the Study:
- To investigate the applicability of macroscopic rate laws for enzyme systems with slow conformational fluctuations.
- To determine if slow enzyme dynamics affect the validity of established kinetic models.
- To analyze the relationship between conformational timescales and catalytic rates.
Main Methods:
- Theoretical investigation of enzyme systems in a quasi-equilibrium limit.
- Analysis of arbitrary reaction schemes with slow catalytic transitions relative to ligand binding/dissociation.
- Numerical simulations for multi-substrate and inhibitor enzyme-catalyzed reactions.
Main Results:
- Enzymatic catalytic rates maintain the same ligand concentration dependence as mass-action kinetics, irrespective of slow conformational fluctuations.
- The timescale of conformational dynamics does not impact the enzymatic rate in the quasi-equilibrium limit.
- Numerical results confirm the theoretical predictions for complex reaction schemes.
Conclusions:
- Macroscopic rate laws are applicable to fluctuating enzyme systems under quasi-equilibrium conditions.
- Slow conformational dynamics do not alter the fundamental ligand dependence of enzyme kinetics.
- The study provides a theoretical framework for understanding enzyme behavior in the presence of dynamic fluctuations.
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