Effect of Temperature and pH on Enzymes

• What is the main function of enzymes?

  They speed up chemical reactions
• What is the effect of temperature on enzyme activity?

  • Enzyme activity increases with temperature
  • Maximum activity at optimum temperature
  • For human enzymes, optimum is 37°C
  • High temperatures can denature enzymes
• What happens to enzyme activity as temperature increases?

  It increases until the optimum temperature
• What is the optimum temperature for most human enzymes?

  37 degrees Celsius
• What occurs when the temperature exceeds the optimum for enzymes?

  Enzyme activity rapidly decreases to zero
• What does it mean when an enzyme's active site is denatured?

  It no longer fits the substrate perfectly
• How does pH affect enzyme activity?

  • Each enzyme has an optimum pH
  • Activity is maximum at optimum pH
  • Extreme pH can denature the active site
  • Example: protease in stomach (acidic), lipase in intestine (alkaline)
• What happens to enzyme activity when pH is altered?

  It drops to zero if too extreme