effect of pH on amylase enzyme

• Amylase is an enzyme produced in the salivary gland in the mouth. It breaks down starch to sugar (glucose). Starch is insoluble and too big to be absorbed into the blood stream
• Independent variable:

  I will change the concentration of the pH. For example, pH4, pH7 and pH10.
• Dependent variable:

  I will measure the time taken for amylase to break down the starch (in seconds).
• Control variable:

  Things i will keep the same are the volume of amylase, volume of starch, concentration of amylase, concentration of starch and the temperature of all chemicals.
• Method

  1. Pipette 2 drops of iodine into each dimple of the spotting tile

  2. Pipette 2cm cubed of buffer (pH) solution, amylase and starch solution into 3 different test tubes

  3. Place test tubes into water bath at 37 degrees Celsius for 5 minutes to all reach same temperature- acclimatise

  4. Pour all of the solutions together and start the stopwatch

  5. Immediately pipette 2 drops of the solution into the iodine in the dimple dish- solution should remain blue or black

  6. Continue pipetting drops of the solution into the iodine every 30 seconds until it stays orange meaning all of the starch has been broken down into sugar and their reaction is finished
• Conclusion:

  pH 7 was optimal because it took 0.035 seconds and the pH of the mouth is 7. The higher pH's were not as effective because enzymes are very specific. Calculate rate of reaction by doing- 1000/time
• Improvements:

  • repeat 3 times to calculate mean and identify anomalies
  • test more buffer solutions (pH 6, pH 8)
  • Measure at smaller time intervals (10, 15 seconds)