Enzyme Catalysis Lab

Materials – at lab station 20 small cups 3 large cups 4 syringes Piece of white paper Dropper Glass beaker Test tube Test tube holder (metal wire thing) Ring stand with burette Funnel Stirring rod Safety goggles Glass bowl for ice Small graduated cylinder Large graduated cylinder Sharpee Marker

Materials – to pick up from center station - Ice - 1.5% H 2 O 2 – 90 mL - OVERNIGHT H 2 O 2 – 10 mL - Catalase – 20 mL (KEEP ON ICE!!) - 1M H 2 SO 4 – 100 mL (careful – ACID!) - KMnO 4 – 25 mL (put in burette!)

Finding Baseline: Procedure 1. First you need to set up the burette. Using the funnel, fill the burette with KMnO 4. Make sure not to fill it past the measuring lines because you will need to be able to read it. 2. Put l0 mL of 1.5% H 2 O 2 into a clean small cup. 3. Add 2 mL of H 2 O ( instead of enzyme solution ). 4. Add 10 mL of H 2 SO 4 (1.0 M)(ACID!). 5. Mix well. 6. Remove a 5 mL sample. Place this 5 mL sample into a different small cup and assay for the amount of H 2 O 2 as follows: Place the beaker containing the sample (5 mL) over a piece of white paper. Note the INITIAL level of KMnO 4 (potassium permanganate; purple color) in the burette to start and record that information in Table 1.1 below. Use the burette to add KMnO 4, one drop at a time, to the solution until a persistent pink or brown color is obtained. Once the color stays brownish and does not return to clear, stop adding the KMnO 4 and note the FINAL level. Record that information on Table 1.1. Remember to gently swirl the solution after adding each drop. Check to be sure that you understand how to read the burette.

So basically…. 10 mL H 2 O mL H 2 O + 10 mL H 2 SO 4  22 mL Take a 5mL SAMPLE and then titrate it using the KMnO 4

Finding Amount of H 2 O 2 Decomposed  Do the exact same steps as the baseline procedure except use OVERNIGHT H 2 O 2 instead of fresh.