Instructions for the Catalase Lab Report

This will be an individual lab report. Each group will perform the experiment and collect the data but the actual writing is to be done on an individual basis.

The lab report will be divided into two parts, (A) and (B) respectively.

(A)

(1) Describe the ammonium sulfate fractionation of the liver extract that we prepared and the results.

(2) Describe how the ammonium sulfate fractionation works (use internet sources to answer this)

(B)

(1) Describe the activity assay that we performed.

(2) Prepare a plot of the product (oxygen) versus time. Remember that time is usually an independent variable. From your plot estimate the initial rate (micromole per sec is best). Probably best to use the the difference between T₁ and T₀ .

To find the moles product use the equation:

5 H₂O₂ + 2 KMnO₄ + 3 H₂SO₄ à

K₂SO₄ + 2 MnSO₄ + 8 H₂O + 5 O₂

Examine the equation. Moles product produced (oxygen) equal moles reactant or substrate (hydrogen peroxide) utilized. So you convert the difference between T₀ and T₁ to moles hydrogen peroxide utilized and that then equals the moles oxygen produced. You divide that by the time difference between T₀ and T₁ in seconds and you have the rate of oxygen produced per second.

To get the moles hydrogen peroxide utilized you take the volume of permanganate required to titrate at T₁ and subtract that from the volume of permanganate required to titrate the reaction at T₀.

You then convert that amount to moles by multiplying molarity of permanganate times the volume (remember to convert to L). You then convert that to moles hydrogen peroxide by multiplying by the ratio of hydrogen peroxide:permanganate in the chemical equation.

(3) Explain the effect of pH and temperature on catalase activity. Draw two graphs of what you would expect to see and label appropriately.