Enzymes are biological catalysts that carry out thousands of chemical
reactions that occur in living cells. They are a class of proteins
that have a unique three dimensional structure that allows it to bind
with a specific substrate to facilitate a
reaction. Many biological reactions will not occur spontaneously in
the cell; there is simply not enough energy for the reaction to take
place. Enzymes make these
reactions possible by lowering the reactionÂ’s activation energy. Each
cell has tens of thousands of different enzymes that collectively
allow both the break down and synthesis of molecules to drive all
This investigation will explore the effect of pH on the
three-dimensional structure of a protein. Much of the
three-dimensional structure of an enzyme is held together by
weak interactions including H-bonds, ionic bonds, and hydrophobic
These interactions can be easily disrupted by changes in temperature,
concentration, and pH. pH levels out of the normal intracellular range
denature enzymes, slowing the enzymeÂ’s reaction rates.
Hydrogen peroxide (H2O2) is a toxic chemical that is continually being
By product of reactions in peroxisomes of living cells. Since it is
poisonous, the cells
must either get rid of it or change it to something nonpoisonous. If
they cannot do
this, the cell may die; catalase solves this problem. The enzyme
catalase is found in animal and plant tissues, and is especially
abundant in plant storage organs such as potato tubers, corns, and
fleshy part of fruits. Catalase reacts with the H2O2 to form water and
2H2O2 + Catalase â†’ 2H2O + O2 + Catalase
What is Catalase?
Enzymes are very large and complex organic molecules that are
synthesized by the cell to perform very specific functions. These
biological catalysts are important because they speed up the rate of
the reaction they catalyze that would otherwise be too slow to support
life. Catalase is an enzyme present in the cells of plants, animals
and aerobic (oxygen requiring) bacteria. It promotes the conversion of
hydrogen peroxide, a powerful and potentially harmful oxidizing agent,
to water and molecular oxygen.
2H2O2 to 2H2O + O2
Catalase also uses hydrogen peroxide to oxidize toxins including
phenols, formic acid, formaldehyde and alcohols.
H2O2 + RH2 to 2H2O + R
Where is it found and what does it do?
Catalase is located in a cell organelle called the peroxisome.
Peroxisomes in animal cells are involved in the oxidation of fatty
acids, and the synthesis of cholesterol and bile acids. Hydrogen
peroxide is a byproduct of fatty acid oxidation. White blood cells
produce hydrogen peroxide to kill bacteria. In both cases catalase
prevents the hydrogen...