Investigating Enzymes: The Science of Speeding Reactions

Enzymes are nature's catalysts, but how do we measure and explore their activity?

 

Key Factors to Investigate

1. Temperature:
   • How does heat or cold affect enzyme activity?
2. pH:
   • Which pH levels help enzymes work best?
3. Substrate Concentration:
   • Does more substrate make the reaction faster?

 

How to Investigate Enzyme Activity

Step 1: Choose an Enzyme and Substrate

• Example 1: Enzyme: Amylase (in saliva) breaks down starch into maltose.
• Example 2: Enzyme: Catalase (in potatoes or liver) breaks down hydrogen peroxide into water and oxygen.

 

 

Step 2: Set Up the Experiment

Equipment:

• Test tubes
• Enzyme solution (e.g., amylase or catalase)
• Substrate solution (e.g., starch or hydrogen peroxide)
• pH buffer solutions
• Stopwatch
• Thermometer
• Water bath

 

 

Step 3: Conduct the Experiment

Example: Measuring the Effect of Temperature on Amylase

1. Prepare Solutions:

   • Add starch solution to a test tube.
   • Add amylase enzyme to another test tube.

2. Control Temperature:

   • Place both tubes in a water bath set to a specific temperature (e.g., 20°C, 37°C, or 60°C).

3. Mix and Start Timer:

   • Combine the starch and amylase, then start the stopwatch.

4. Test for Starch Breakdown:

   • Every 30 seconds, take a drop from the mixture and add iodine.
   • Iodine turns blue-black if starch is present.

5. Record Results:

   • Time how long it takes for the iodine to stop changing color (indicating starch is fully broken down).

6. Repeat at Different Temperatures:

   • Repeat the experiment at different temperatures and compare the times.

 

Results and Analysis

Graphing Your Results

• Plot a graph of enzyme activity vs. temperature.
• The peak of the curve represents the optimum temperature.