1. An enzyme that breaks down hydrogen peroxide.
Catalase
An enzyme that breaks down hydrogen peroxide.

2. What is hydrogen peroxide?
Hydrogen peroxide is H2O2
It is a colourless liquid, used in disinfectants and hair bleach
It is unstable – it will break down over time
It breaks down into water and oxygen
H2O2 H2O +O2

3. Hydrogen Peroxide and Cells
Hydrogen peroxide is a waste product of cell metabolism
It is dangerous to cells
Cells produce an enzyme to make it break down faster because the products (oxygen and water) are safe
The enzyme they use is called catalase

4. How fast does catalase work?
Catalase can produce up to 200,000 reactions every second.
Q What would make the reaction speed up?
Ans Increasing the temperature (but not too high), or increasing the concentration of catalase

5. Not only catalase but also…
Some metals can act as catalysts to speed up the break-down of hydrogen peroxide.
These include iron, copper and silver

6. Catalase White blood cells produce hydrogen peroxide to kill bacteria
White blood cells would be damaged by the hydrogen peroxide that they produce if they did not contain catalase