Amee Kelley
Biology 101 Lab
Lattimore
3 October 2010

The Conditions that Effect Enzyme Activity
Abstract: Enzymes are proteins that help chemical reactions happen faster. There are optimal conditions for each enzyme. The enzyme likes to work best at higher concentrations and a neutral pH. The data collected supports this idea. The results could be a little off due to errors made in the gathering of the data.
Introduction: Enzymes are a type of catalytic protein.(DeHay, G. 2009) They are important to chemical reactions because they lower the activation rate and change the substrate into usable products. The enzymes are not changed nor are they used up during the chemical reactions. They are recycled and used many times because they are able to remain in their original compositions. By raising the reaction rate, the enzymes enable the chemical reactions to happen easier and faster. Enzymes have specific conformations which allow them to bind with only the substrate that they match with (Koshland). The substrate is the molecule that the enzyme binds with the form a product. Catalysis occurs in the active site of the enzyme. The substrate, co-enzymes, and any inhibitors bind to this site. If the substrate does not match the shape of the active site it will be rejected. Often even isomers of the substrate will be rejected. Once the proper substrate enters the active site induced fit occurs. Induced fit is the process in which the enzyme conforms to the molecule to all for more efficient catalysis. Each enzyme has an optimal condition in which they perform properly. Substrate concentration and pH both effect the way an enzyme works. Once the pH levels change from the optimal levels the enzyme becomes denatured and stops working. The substrate concentration also affects the enzyme. Once the enzyme has changed all of the substrates into products the chemical reaction rate drops. The study is performed to see at what pH and substrate to enzyme concentration the enzyme catecholase works at optimal levels. Catecholase works best at a neutral pH and with a higher substrate to enzyme concentration. Adversely pH and substrate concentration have nothing to do with the enzyme activity.

Methods and Materials: The first thing that was done in this lab was to prepare five blanks each containing 9mL of different pH buffers, 1mL potato juice, and 1mL of water. The test tubes where all labeled with the pH number followed by the letter “B”. The group then proceeded to make five more test tubes following the given chart. The five extra test tubes where the same as the first just with 1mL of catechol to each tube. The tubes were then cover with Parafilm and then inverted several times. They were allowed to react for five minutes, inverted at one minute intervals. The tubes where then used to fill a cuvette that corresponded to a certain solution. The blanks where then used before each corresponding solution on the spectrophotometer. The readings were taken on a spectrophotometer at 420 nm. The second part of the lab was to test the effect of enzyme concentration on catecholase activity. The groups labeled four test tubes and added the required contents to each tube. The contents where then mixed thoroughly. The spectrophotometer was set to a wavelength of 420 nm. The blanks were then used before the actual test specimen to adjust to spectrophotometer. Only one test tube was done at a time because the catechol had to be added right before the testing. Each cuvette was then tested at one minute intervals for six minutes. The results were recorded in the provided table.
Results: In the chart pH effects on Enzyme