Lecture Notes: Understanding Enzymes and Activation Energy

Introduction

• Lecturer has a sore throat, voice may crack.
• Thanks to audience for previous support.

Main Topic: How Enzymes Work

• Enzymes bind to substrates to lower activation energy.
• Activation energy is the energy required for a chemical reaction.

Example Explanation

• Disaccharide Example: Two monosaccharides linked by a glycosidic bond.
  • To break the bond via hydrolysis, water is required.
  • At 30°C, water lacks kinetic energy to break the bond.
  • At 100°C, water has enough kinetic energy to effectively break the bond.

Enzyme Functionality

• Energy Levels: Hydrolysis is exothermic; reactants have higher energy than products.
• Role of Enzymes:
  • Enzymes are globular proteins.
  • Comprised of amino acids; represented as Pac-Man shape.
  • Active site of enzyme must be complementary (not the same) to the substrate.
  • The active site interacts with the glycosidic bond to weaken it.
  • Allows hydrolysis at lower temperatures (e.g., 37°C).

Enzyme Structure

• Enzymes are made of polypeptide chains.
• Protein Structure:
  • Primary: Sequence of amino acids.
  • Secondary: Alpha helix and beta pleated sheets.
  • Tertiary: Fully folded structure, forming active site.

Important Concepts

• Complementary Shape: Enzymes and substrates have matching shapes.
• Active Site: Contains R groups that interact with the substrate.
• Activation Energy Reduction: By binding and weakening the substrate bonds.

Enzyme Reusability

• Enzymes are catalysts: they reduce activation energy and are reusable.
• After reaction, enzymes move to the next substrate.

Additional Notes

• Enzymes don't just catalyze hydrolysis; they are involved in various reactions.
• Enzymes facilitate reactions without being consumed.

Summary

• Enzymes play a crucial role in reducing the energy required for reactions.
• They make processes like hydrolysis more efficient at lower temperatures.