The Working of a Biological Catalyst: Catalase

To investigate the working of a biological catalyst: catalase

The topic being investigated was the working of a biological catalyst. An enzyme is a protein that acts as a biological catalyst of chemical reactions and is capable of speeding chemical reactions. The shape of each enzyme is very precise and this gives the enzyme the ability to catalyze one specific reaction. Enzymes have a three dimensional shape, which is essential to the way it functions. In every enzyme there is a region called active site where a complementary substrate molecule binds with it. After this, and the enzyme is ready to bind with other molecules and the process repeats itself. However, enzymes require certain conditions to work effectively. Temperature, pH and the concentration of the substrate all affect enzyme activity. Catalase is a specific kind of enzyme and is found in almost all living organisms that are exposed to oxygen. Catalase can be found for example in the liver where it breaks down hydrogen peroxide into water and oxygen. When this reaction occurs, oxygen gas bubbles escape and create foam.

In tube 1 there was 4ml of water and a cube of liver. Catalase did not break down hydrogen peroxide as liver was placed into water. Oxygen gas bubbles were created, but the solution did not foam. Enzyme activity was not affected as the pH of water, which is 7, is similar to the pH the liver maintains.

In tube 5 a boiled cube of liver was placed into hydrogen peroxide. Boiling liver made irreversible changes to the structure of catalase and it could no longer function properly, it become denatured. Boiling liver damaged the catalase enzyme and clearly decreased the amount of bubbles when it was exposed to hydrogen peroxide; no foam was created. ...

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...fect. This is shown in Figure 3.

Figure 3 The effect of substrate concentration on enzyme activity (http://alevelnotes.com/content_images/i73_Image3.gif)

As a conclusion, catalase being an enzyme requires specific conditions in order to work at its greatest efficiency. Temperature, pH and substrate concentration are all factors that affect enzyme activity, and if these are altered the enzyme activity will either increase or decrease. Catalase is an enzyme found in the liver which breaks down hydrogen peroxide into water and oxygen. This creates oxygen gas bubbles to escape and create foam. As one of the three factors stated above is altered, the catalase activity is affected and there will be either more foam, less foam or no foam at all. This is because they all affect the rate at which enzymes operate and produce their products.