Enzymes

• Add a few drops of iodine solution to each dimple in a spotting tile
• Add a fixed volume of starch, amylase and pH buffer solutions to a water bath at a set temperature. Leave for 5 minutes
• Mix the starch solution and amylase solution together
• Every 30 seconds add a few drops to the spotting tile. Repeat until the iodine does not turn blue/black
• Repeat for different pH's or different temperatures
• Iodine is used to test for presence of starch
• A positive test result for starch is a blue/black colour change
• Amylase breaks down starch
• If amylase was added to the mixture you would expect starch to be broken down
• You should use a water bath to keep solutions at a certain temperature
• You should expect amylase to work best at 37*C
• You should test your mixture for presence of starch every 30 seconds
• At high temperatures you would expect no starch to be broken down because the enzyme would have been denatured
• At low and high PH's you would expect no starch to be broken down because the enzyme would have been denatured
• You should leave the solutions in the water bath for atleast 5 minutes before testing to allow the solutions to get to the same temperature
• You would expect starch to take longer to disappear at low temperatures because molecules have low kinetic energy and so fewer collisions between starch and amylase
• You could use this experiment to determine the the temperature or pH amylase works best by looking for the quickest time that iodine stopped turning blue/black