Enzymes are catalysts. Most are proteins. (A few ribonucleoprotein enzymes have been discovered and, for some of these, the catalytic activity is in the RNA part rather than the protein part. Link to discussion of these ribozymes.)
Enzymes bind temporarily to one or more of the reactants — the substrate(s) — of the reaction they catalyze. In doing so, they lower the amount of activation energy needed and thus speed up the reaction.
3.6.4 Denaturation of enzymes
Monday, 21st Jan Lab: Catalase from potatoes
“In animals, such as us, oxidative molecules are most often produced through our metabolizing of food molecules. So the presence of catalase makes sense. Plants do not eat, so why would they need catalase? If we study the process of photosynthesis we may come across a term called photorespiration. Photorespiration simply is when a plant receives too much light and not enough water. As a result, the plant can produce large amounts of hydrogen peroxide which can kill the plant. Fortunately, catalase prevents the accumulation of hydrogen peroxide by converting it to water and oxygen, and so saves the plant from oxidative damage.” (http://practicalbio.blogspot.com/2012/03/easy-enzyme-experiment-potato-catalase.html)
Studying the effect of temperature on Catalase:
0.5 tsp mashed potato in each test tube
1.0ml distilled water
Keep these test tubes at different temperatures for 3 minutes for them to arrive at the required temperature( Very cold; cold; room temperature; warm, hot; very hot)
Add 5.0ml of H2O2 solution and wait for 1 minute.
Measure the level of foam formed in each test tube once the H2O2 has been added.
Record all the readings in a data table you have created.
Use filter paper discs coated with the Catalase and note the time taken for the disc to rise.
3.6.5: Enzymes for commercial purposes / everyday use
Feb 5, 2013
Option c.2.4 / AHL 7.6.4
Inhibition of enzyme action