Enzyme Lab - Catalase Activity
Enzymes are usually
more efficient than man-made catalysts operating under the same conditions.
Because enzymes catalyze almost all of the biochemical reactions in the
cell (producing and breaking down bazillions of molecules), each enzyme
must be very efficient. One molecule of the enzyme catalase
for example, when breaking down peroxide, produces 10^12 molecules
of oxygen per second.
Enzymes have a special affinity for the substrate. They fit together, matching in shape and charge. The part of the enzyme where the substrate fits, is called the active site. The amino acids in the active site are in the right 3D conformation to bind and modify the substrate.
The combination of substrate molecules with enzymes also involves collisions between the two. The substrate must reach the active site. As the substrates are used up during a reaction (converted to products), the chance of their colliding with the enzyme decreases, this results in a decrease in the amount of product being produced (aka a lowered reaction rate).
In this week's lab we will measure the rate of a reaction by measuring
the amount of 
substrate
remaining after some period of time. This is a little unusual. In
our reaction, H2O2
is the substrate and H2O2
is converted to H2O + O2
as the reaction proceeds. Rather than measuring the formation of Product
(H2O + O2)
as an indicator of the reaction, we will measure the disappearance of
the substrate (H2O2).
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Let's see if you were paying attention:
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2. If we had repeated the experiment, measured and found 2.5 ml of H2O2 remaining, would this second reaction have a higher or lower rate of reaction?
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