Factors affecting enzyme action

• What factors affect enzyme activity?

  pH, temperature, and concentration
• Why must enzymes be the right shape for their substrate?

  To ensure proper binding and catalysis
• How does temperature affect enzyme activity?

  Higher temperatures increase kinetic energy and collisions
• What is the temperature coefficient, Q10?

  It measures reaction rate increase per 10°C rise
• What happens to enzymes at high temperatures?

  They can denature and lose their function
• What is denaturation in enzymes?

  Change in enzyme shape affecting function
• What is the optimum temperature for most human enzymes?

  Around 40°C
• How do thermophilic bacteria adapt to high temperatures?

  Their enzymes have more stable structures
• Why do Siamese cats have white fur?

  Tyrosinase is inactive at normal body temperature
• What is the effect of pH on enzyme activity?

  Changes in pH can denature enzymes
• What happens to the active site when pH changes?

  It can become altered and non-functional
• How does the concentration of substrate affect enzyme activity?

  Increased concentration raises reaction rate
• What is Vmax in enzyme reactions?

  The maximum rate of reaction achievable
• What is catalase and its function?

  It breaks down hydrogen peroxide into water and oxygen
• What would happen if liver tissue is boiled before reaction with hydrogen peroxide?

  The enzyme catalase would be denatured
• What are the optimum pH conditions for various digestive enzymes?

  • Amylase: neutral (pH 7-8)
  • Pepsin: acidic (pH 1-2)
  • Trypsin: slightly alkaline (pH 8)
  • Lipase: slightly alkaline (pH 8)
  • Maltase: neutral (pH 7)
• What are the effects of temperature extremes on enzyme activity?

  • Enzymes in cold environments: more flexible, less stable
  • Enzymes in hot environments: more stable due to extra bonds
  • Small temperature changes can denature cold-adapted enzymes
• How does the concentration of enzyme affect reaction rate?

  • Increased enzyme concentration raises available active sites
  • More enzyme-substrate complexes form
  • Reaction rate increases until Vmax is reached
• What is the relationship between substrate concentration and enzyme activity?

  • Higher substrate concentration increases reaction rate
  • Reaction rate increases until all active sites are occupied
  • After Vmax, further increases in substrate do not affect rate
• What is the significance of the shape of the graph showing enzyme activity against pH?

  • Symmetrical graph indicates reversible reduction in activity
  • Activity decreases as pH moves away from optimum
  • Unlike temperature graphs, pH effects are reversible up to a point