Effect of Temperature on Rate of Reaction of Catalase

Effect of Temperature on Rate of Reaction of Catalase

Introduction

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.

Method

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.

Results

See Overleaf.

Conclusion

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 ...

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...at the surface area would not be equal all the way

through the experiment. A small surface area error would probably lead

to a large rate of reaction mis-calculation. The reaction itself

caused heat because it is an exothermic reaction which could alter the

rate of reaction in itself. During the reaction substrate was used up

which caused the reaction to slow to a halt after a while despite the

fact that the enzymes were still functional, more substrate than was

needed would have countered this and given true readings. Perhaps the

most serious error in the whole experiment though was the fact that

the gas expanded as the temperatures rose which would throw the

results off completely. In order to counter this, the gas would need

to be collected and cooled to room temperature in order to get

perfectly accurately results.