Understanding:
• Enzyme catalysis involves molecular motion and the collision of substrates with the active site
Enzyme reactions typically occur in aqueous solutions (e.g. cytoplasm, interstitial fluid, etc.)
- Consequently, the substrate and enzyme are usually moving randomly within the solution (Brownian motion)
- Sometimes an enzyme may be fixed in position (e.g. membrane-bound) – this serves to localise reactions to particular sites
Enzyme Catalysis
Enzyme catalysis requires that the substrate be brought into close physical proximity with the active site
- When a substrate binds to the enzyme’s active site, an enzyme-substrate complex is formed
- The enzyme catalyses the conversion of the substrate into product, creating an enzyme-product complex
- The enzyme and product then dissociate – as the enzyme was not consumed, it can continue to catalyse further reactions
Enzyme-Substrate Interactions
Collision Frequency
The rate of enzyme catalysis can be increased by improving the frequency of collisions via:
- Increasing the molecular motion of the particles (thermal energy can be introduced to increase kinetic energy)
- Increasing the concentration of particles (either substrate or enzyme concentrations)
Summary of Enzyme-Substrate Kinetics
Link: Enzyme Catalysis Simulation