Enzyme Catalase

The enzyme catalase speeds up the decomposition of Hydrogen Peroxide into water
and oxygen as shown here, 2H2O2-------------------*2H2O+O2. It is one of the
fastest known enzymes and its turnover number is 6 million, which means the
number of substrate molecules which one molecule of the enzyme turns to products
per minute. This can be demonstrated by putting a piece of liver into a beaker
of Hydrogen Peroxide, the fizzing shows a demonstration of the enzyme in action.

AIM My aim is to examine how the concentration of the substrate hydrogen
peroxide affects the enzyme catalase. INVESTIGATION I am going to investigate
the effect of varying the substrate concentration on enzyme catalase. I am going
to use 8 different concentrations and record the time taken to collect 20ml of
gas in the gas syringe. I will repeat all the 8 concentrations twice so I can
see if they match, spot out any anonymous results and also I can work out the
average time it takes to produce 20ml of gas at the certain concentrations. I
will vary the concentrations by increasing and decreasing the amounts of

Hydrogen Peroxide and water. PLAN First of all I will ensure I have enough
enzyme solution for the whole experiments so the enzyme solution is standardised.

With the results I get I will try to work out the Vmax. I will do this
experiment at room temperature so the enzymes get enough kinetic energy to
collide. I will need 80ml of the enzyme solution because I will use 5ml for all
of the experiment and I will do 8 different concentrations and I will repeat
this concentrations twice so that is 5x8x2= 80. First of all I will set out the
equipment as I will show in the diagram then I will cut some pieces of liver,
which is the source of the enzyme. Then I will grind the pieces of liver with
the mortar and pestle, which will have sand and Di ionised water (which is water
with no H ions in it its PH is neutral). The sand will help cut open the cells
of the liver. I will take a funnel with glass wool in it, I chose glass wool
rather than filter paper because the catalase could have been adsorbed by the
filter paper. Then I will add 5ml of the enzyme catalase to the conical flask
and for the substrate concentration of 10% I will add 2ml of Hydrogen Peroxide
and 18ml of water (18+2= 20, I will always use 20ml) every time I when I will
increase the concentration by 10% I will increase the H2O2 by 2ml and decrease
the H2O by 2ml. I will time how long it takes to produce 20ml of gas in the gas
syringe. I chose the gas syringe rather than to count the bubbles produced in a
measuring cylinder because it is easier to use, the results will be more
accurate and the gas syringe reduces the possibility of gas escape. I will
tabulate my results and highlight them in some way so they are visible I will
interpret my results in to a line graph. I will also added a line of best fit to
the results on the graph and with the results I get I will work out the Vmax.

Here is a blank copy of my results table, which I fill in later when I get my
results. FAIR TEST To make my experiment a fair test I need to ensure that all
the variables must be kept the same for all the experiments except for the
concentration of Hydrogen Peroxide. I will accurately measure out the Hydrogen

Peroxide and enzyme solution using a pipette and measuring cylinder. I will use
glass wool rather than filter paper because if I use filter paper then the
catalase could be adsorbed by the filter paper, which will no longer make my
experiment a fair test. I will time how long it takes to produce 20ml of gas by
using a stopwatch accurately. For each concentration I will make sure that there
is no excess catalase or substrate in the measuring cylinders I use by cleaning
them. I will hold the rubber bung connecting the conical flask and the gas
syringe so it does not open and let out any gas. PREDICTION I predict that the
more the concentration of substrate the faster it will be to produce 20ml of
oxygen if you increase the concentration there will be a higher chance of
collision between the particles, but there will come a point