Factors effecting enzyme action

• Enzyme specificity


  Enzyme will only work on one (or a very small range of) substrates
• Factors affecting enzyme action

  • Temperature
  • pH
  • Enzyme concentration
• Optimum


  Maximum rate of enzyme activity
• Effect of temperature on enzyme activity

  1. Low temperature reduces collisions between substrate and enzyme

  2. Increased temperature increases kinetic energy and collisions

  3. Optimum temperature for maximum activity

  4. Above optimum, enzyme denatures and activity decreases
• The changes in enzyme active site shape that take place when enzymes are heated above their optimum temperatures are irreversible
• Effect of pH on enzyme activity

  1. Optimum pH for maximum activity

  2. Activity decreases above or below optimum pH due to changes in active site shape
• Optimum pH for most human enzymes is pH 7
• Effect of enzyme concentration on enzyme activity


  1. More enzymes = faster rate of reaction

  2. Rate levels off as substrate becomes limiting
• Inhibitors


  Molecules that fit loosely into an enzyme's active site, stopping the normal substrate from fitting
• Inhibitors are not broken down by the enzyme
• Low temperatures


  Reduce rates of collision between substrate and enzyme
• Increased temperatures


  Increase kinetic energy and collisions between enzyme and substrate
• Temperatures above optimum


  Enzyme denatures, reducing activity
• pH above or below optimum

  Enzyme active site shape changes, reducing activity
• More enzymes = faster rate of reaction, but rate levels off as substrate becomes limiting
• Inhibitors fit into active site but are not broken down, reducing normal enzyme activity
• Enzymes are biological catalysts that speed up chemical reactions without being used up or changed themselves.
• effect of Enzyme Comcentration on enzyme activity

  
• effect of PH on enzyme activity

  
• effect of Temperature on enzyme activity

  
• Effect of Inhibitor concentration on enzyme activity
• Effect of Substrate concentration on enzyme activity
• enzymes have an optimum temperature at which they work best
• Enzyme example question