Factors affecting activity enzymes

• Enzymes


  • Require specific conditions to work effectively
  • If conditions are not present, the enzyme catalysed reaction will slow down or not work at all
• Factors affecting enzyme catalysis

  1. Temperature

  2. pH

  3. Concentration
• Optimum temperature


  The temperature at which an enzyme works fastest
• As temperature increases up to the optimum temperature


  The reaction rate increases
• Beyond the optimum temperature

  There is energy-fever collisions, the reaction rate is slower
• Above the optimum temperature

  Hydrogen bonds in enzyme break, active site loses its shape (denatured), no catalysis
• For many enzymes in the body, the optimum pH is between 7 and 8 as this is the pH of most body cells
• Some enzymes have a more extreme optimum pH, for example, pepsin (a stomach enzyme) has an optimum pH of about 1
• pH affects the charge on the active site


  If pH changes, the charges on the active site change, and the substrate may no longer be able to bind to it
• Increase in substrate concentration

  Increases the rate of collisions, increases the reaction rate
• Increase in enzyme concentration

  Increases the rate of collisions, increases the reaction rate
• If substrate concentration is too high

  There will be no more active sites for them to bind to, increasing substrate concentration will no longer affect the rate
• If enzyme concentration is too high

  There are too many free available active sites compared to substrate molecules, the rate of reaction will no longer increase
• Protease is an enzyme found in the stomach, where the pH is low