Related Experiment Video
Updated: May 16, 2026
08:31
Probing Surface Electrochemical Activity of Nanomaterials using a Hybrid Atomic Force Microscope-Scanning Electrochemical Microscope (AFM-SECM)
Published on: February 10, 2021
Exploration of two-enzyme coupled catalysis system using scanning electrochemical microscopy
Zeng-Qiang Wu1, Wen-Zhi Jia, Kang Wang
1State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China.
Analytical Chemistry
|November 28, 2012
Summary
This study uses scanning electrochemical microscopy (SECM) to investigate enzyme kinetics in coupled reactions. The research reveals choline oxidase is the rate-limiting step in this two-enzyme system.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Chemical Kinetics
Background:
- Metabolic processes involve sequential enzyme pathways, necessitating understanding of multienzyme catalysis.
- Studying enzyme kinetics in coupled systems is crucial for biological mechanism exploration.
Purpose of the Study:
- To develop and apply a novel approach using SECM combined with numerical simulations to study the kinetics of a two-enzyme coupled reaction.
- To measure the overall apparent Michaelis-Menten constant and evaluate individual enzyme kinetic parameters.
Main Methods:
- Immobilization of acetylcholine esterase and choline oxidase on gold electrodes of SECM.
- Utilizing SECM to precisely regulate tip-substrate separation distance and measure reaction kinetics.
- Establishing a kinetic model using the finite element method for parameter evaluation.
Main Results:
- Measured an overall apparent Michaelis-Menten constant of 2.97 mM at an optimal gap of 18 μm.
- Demonstrated that the choline oxidase catalytic reaction is the rate-determining step.
- Evaluated the Michaelis-Menten constant for acetylcholine esterase as 1.8 mM.
Conclusions:
- The proposed SECM approach provides a promising method for exploring mechanisms of two-enzyme coupled reactions.
- This study advances the development of biosensors and enzyme-based logic systems.
Related Concept Videos
01:13Introduction to Mechanisms of Enzyme Catalysis
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes a mild...
01:13Introduction to Mechanisms of Enzyme Catalysis
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes a mild...
01:22Overview of Microscopy Techniques
The early pioneers of microscopy opened a window into the invisible world of microorganisms. In 1830, Joseph Jackson Lister created an essentially modern light microscope. The 20th century saw the development of microscopes that leveraged nonvisible light, such as fluorescence microscopy that uses an ultraviolet light source and electron microscopy that uses short-wavelength electron beams. These advances significantly improved magnification, image resolution, and contrast. By comparison, the...
01:19Enzyme Kinetics
Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called the rate of reaction. Several factors impact the rate of reaction, including the number of available reactants. Enzyme kinetics is the study of how an enzyme changes the rate of a reaction.
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
01:19Introduction to Enzyme Kinetics
Enzyme kinetics studies the rates of biochemical reactions. Scientists monitor the reaction rates for a particular enzymatic reaction at various substrate concentrations. Additional trials with inhibitors or other molecules that affect the reaction rate may also be performed.
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...
The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a...
01:00Enzyme-linked Receptors
Enzyme-linked receptors are proteins that act as both receptor and enzyme, activating multiple intracellular signals. This is a large group of receptors that include the receptor tyrosine kinase (RTK) family. Many growth factors and hormones bind to and activate the RTKs.
Neurotrophin (NT) receptors are a family of RTKs, including trkA, trkB, and trkC (tropomyosin-related kinase) receptors. TrkA is specific for nerve growth factor (NGF), neurotrophin-6, and neurotrophin-7. TrkB binds...
Neurotrophin (NT) receptors are a family of RTKs, including trkA, trkB, and trkC (tropomyosin-related kinase) receptors. TrkA is specific for nerve growth factor (NGF), neurotrophin-6, and neurotrophin-7. TrkB binds...