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Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity
Published on: August 19, 2013
The kinetics of substrate-induced inactivation
1Laboratory of Molecular Biophysics, University of Oxford, U.K.
The Biochemical Journal
|October 1, 1991
Summary
This study investigates enzyme kinetics in branched-pathway reactions, detailing how substrate-induced inactivation affects reaction progress curves. Understanding these kinetics allows for accurate determination of key reaction parameters and rate constants.
Area of Science:
- Biochemistry
- Enzyme kinetics
- Chemical kinetics
Background:
- Enzymic reactions can exhibit complex kinetics, including branched pathways.
- Substrate-induced inactivation can lead to transient phenomena like bursts in reaction progress curves.
Purpose of the Study:
- To study the kinetics of a branched-pathway mechanism involving reversible enzyme inactivation.
- To identify parameters obtainable from reaction progress curves and guide accurate rate constant determination.
Main Methods:
- Analysis of a branched-pathway mechanism with reversible formation of an inactive enzyme-substrate complex.
- Characterization of reaction progress curves to extract initial rate, final rate, and transient rate constant.
- Utilizing computer simulations to determine optimal conditions for kinetic parameter measurement.
Main Results:
- The study identifies three key parameters from progress curves: initial rate, final rate, and transient rate constant.
- The rate constant for reactivation from the inactive complex can be derived from these parameters or by measuring activity regain.
- The partition ratio, reflecting the balance between product formation and inactivation, is also obtainable.
Conclusions:
- The kinetics of branched-pathway enzyme reactions with reversible inactivation can be accurately characterized.
- Simulations provide valuable insights into experimental conditions for precise determination of kinetic parameters.
- This work aids in understanding and quantifying complex enzyme mechanisms.
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