Transfer about 5 mL of the standard peroxidase solution to each of six 15 mL centrifuge tubes labeled A through F.

Tube A is the unmodified peroxidase solution.

Cap tube B and place it in the freezer until the solution freezes. When it has frozen, remove the tube and allow the peroxidase solution to melt and come to room temperature.

Place tube C in a hot water bath at boiling or nearly so, and allow it to remain in the bath for 10 minutes or so. Remove the tube and allow the contents to come to room temperature.

Add five drops of 0.1 M lead(II) acetate solution to tube D. Cap the tube and invert it several times to mix the solutions.

Add five drops of 6 M sodium hydroxide solution to Tube E. Cap the tube and invert it several times to mix the solutions.