Effect of Temperature on Rate of Reaction of Catalase
This investigation was in an attempt to try to find out how varying
the temperature can affect an enzyme. The enzyme used was catalase
which breaks down Hydrogen Peroxide, this gives off water and oxygen
as effervescence. This effervescence is what is used to measure the
reaction rate of the catalase. The optimal heat for enzyme activity is
proven to be 37oC as anything above this denatures the enzyme.
Denaturing is where the heat energy of breaks down the di-sulphide,
ionic and hydrogen bonds that hold the tertiary structure together,
this in turn changes the shape of the active site and so halts any
reactions that the enzyme would otherwise be able to catalyze.
6 test tubes were set up and 2cm squared of Hydrogen Peroxide was
placed in each tube. Each tube was then placed in a water bath of the
corresponding temperature (20oC, 40oC, 60oC and 80oC), and one in a
beaker of ice (0oC). They were all left in for 10 minutes to take them
all to the desired temperature before the experiment began.6 strips of
potatoes were then cut to 1cm3 using a ruler and scalpel. One of the
strips was put into each tube and then timed with a stop clock and the
level of froth was measured as it rose up the side of the tube every
20 seconds until the froth started to fall. This was done to each tube
individually so that a more accurate measurement was taken.
The enzymes were at low activity at around 0oC and then a slight rise
all the way up to 40oC (gentle curve), followed by a steep downward
curve or slow in activity up to 60oC then a very strange rise in
activity at 80oC.
As the temperature rose the particles began to vibrate faster, this is
turn caused more collisions between particles. This is why the
reaction rate rose with the temperature, however after a certain point
(40oC), the enzymes were becoming denatured and this caused them to
become useless which is why the reaction slowed to a halt after this
This was a poor experiment because:
The potato chips were very hard to get exactly the same. This