Effect of Ph on Amylase

• pH


  Measure of acidity or basicity of a solution
• Amylase


  Enzyme that breaks down starch into glucose
• Amylase activity


  1. Binds to starch molecule

  2. Breaks down starch into glucose
• Starch is made of glucose
• Starch is broken down into glucose in the body
• Amylase is the enzyme that breaks down starch into glucose
• Foods that contain starch

  • Potato
  • Rice
  • Bread
  • Pasta
• Iodine test for starch


  Iodine is an orange liquid that turns blue-black when it reacts with starch
• Iodine test procedure


  1. Get well plates

  2. Add 1 drop of iodine to each well (control variable)

  3. Prepare amylase solution at pH 4

  4. Transfer 2 cm^3 starch to test tube

  5. Transfer 2 cm^3 amylase solution to starch

  6. Start timer

  7. Every 20 seconds, add 1 drop of starch-amylase solution to iodine well

  8. Continue until iodine no longer turns blue-black
• Iodine remains yellow


  All starch has been broken down into glucose
• Record the time taken for amylase to completely break down starch at pH 4
• Repeat experiment at pH 1

  1. Mix amylase in pH 1 buffer

  2. Add 2 cm^3 amylase-pH 1 solution to 2 cm^3 starch

  3. Add 1 drop iodine to each well

  4. Every 20 seconds, add 1 drop starch-amylase-pH 1 solution to well

  5. Iodine remains blue, no starch breakdown
• At pH 1, the amylase active site has denatured, so it can no longer bind to and break down the starch