Determining Properties of Peroxidase Enzyme
Jeremy Jones and 2:00 Tues. 1406 lab classmates
Biology Department, Tarrant County College, Fort
Normal function of peroxidase enzyme is to convert
hydrogen peroxide to into water and oxygen.
Experiments were carried out to check peroxidase
activity at different concentration levels, pH levels,
temperatures, and check effect of boiling and
Peroxidase is a large protein containing hundreds of
amino acids and has an iron ion located at its active
site. It is easy to obtain and work with, making it an
ideal candidate for lab work. The peroxidase reaction
can be measured by following the increased oxygen
levels. The simplest way to measure oxygen levels is
to test with a dye that reacts to chemically active
oxygen. The dye will turn from colorless to colored in
a dye-coupled reaction. Guaiacol is a dye that turns
brown when oxidized. The enzyme, substrate, and dye
can be mixed together and immediately placed in a
spectrophotometer. The absorbance at 500nm will
increase as more color accumulates.
Hypotheses: 1. More peroxidase activity will be
observed at higher levels of concentration.
2. More peroxidase activity will be observed at
mid-level temperatures and mid-pH levels.
3.Boiling will cause complete denaturation of
4. Hydroxylamine will inhibit all peroxidase activity.
All experiments carried out as per Biological
Investigations, 6th Edition by Warren D. Dolphin. See
Lab Topic 6, Determining the Properties of an Enzyme.
1. Peroxidase activity increased steadily with
increased concentration. Tubes 6 and 7 with 2 ml of
extract actually went off the absorbance scale at 100
2. Temperature was measured from 4 degrees Celsius to
48 degrees Celsius. Optimum results were obtained at
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