Enzyme Catalysis Lab

Purpose:
The purpose of this experiment is to understand the functions of enzymes and how pH changes the reaction rate. This can be done by observing the enzyme catalase in the break down of hydrogen peroxide (H2O2) into water (H2O) and oxygen gas (O2), and measuring the amount of oxygen generated and the rate of the enzyme-catalyzed reaction.

Introduction:
Enzymes are proteins that act as catalysts in biochemical reactions; catalysts affect the rate of a chemical reaction. In enzyme-catalyzed reactions, the substrate binds to the active site of the enzyme, and the activation energy of the reaction is lowered so that the produced can be formed more easily. Ways in which enzyme action can be affected include salt concentration, temperature, pH, and activations/inhibitors. 

Methods:
The main point in this lab was to understand enzyme activity. We did this by collecting baseline trials of the rate of reaction of the uncatalyzed reactions. Next we would use the same process to collect data of the catalyzed reactions, after we had added the enzyme Catalase. Then we compared the trials of the two types of reactions to one another and observed what happened to the rate of reaction.

Data:

                     

 

Graphs:


                              



Discussion:

 In this lab, we tested the affect of denaturing enzymes and how that relates to the rate of reaction between two substances.  The substances we tested were catalase,which is an enzyme, and hydrogen peroxide, which is a substrate.  In order to denature the enzyme, we added an acid, H2SO4.  The results we got indicated a direct curve, with a few exceptions.  When aci was added after 90 seconds, there was a slight decrease in rate of decomposition, which did not fillow the trend of increasing rate of reaction.  Also, at 180 seconds, there was a slight decrease as well which did not follow the trend.  This could be caused by a few things.  One, we may have put the acid in slightly too early, which would have caused this decrease.  Two, we may have contaminated the beaker with leftover acid from other experiments and the denaturing could have occurred too early, causing less decomposition to occur.  But, on average, we observed that as an enzyme is left with a substrate for a longer time, more decomposition occurs.  Therefore, length of time the substrate is exposed to the enzyme and amount of decomposition are directly related.  

Conclusion:
We can conclude that concentration of enzymes directly related to rate of decomposition of H2O2.

References:

Campell Biology, 2009