SUBSTRATE AND ENZYME REACTION

Substrate and Enzyme Reaction Lab Report



Substrate and Enzyme Reaction Lab Report

Statement of the Problem

Amount of reaction produced with an enzyme and substrate with varying levels of each, as well as varying time allotted to reaction.

Enzymes are catalytic proteins, meaning they speed up chemical reactions without being used up or altered permanently in the process. Although various enzymes use different methods, all accomplish catalysis by lowering the activation energy for the reaction, thus allowing it to occur more easily. Enzymes have very specific shapes (conformations). (Daniel et al 2010) Part of the conformation is the active site of the enzyme, where the actual catalysis occurs. The specific molecule or closely related molecules on which an enzyme functions is known as its substrate. Shape plays such an important role in enzymatic catalysis that often even isomers of a substrate will be rejected. Once the substrate enters the active site, it may begin a process known as induced fit in which the enzyme perfectly conforms to the molecule to allow for more efficient catalysis. (Duhr 2006) Changes in environment can severely impact enzyme catalysis in both negative and positive ways. Each enzyme has specific ranges at which it optimally functions; in general, increasing the temperature will help the reaction along, until the point at which the protein degrades and denatures. Denatured proteins will often return to their original state, after the removal of the denaturing agent, except when they are degraded multiple levels. (Passonneau 1993)

Hypothesis

As the surface area gets larger, the reaction rate will increase.

The reaction rate will be the fastest when the temperature is at 37°C, and very high temperature (boiling) will denature the enzymes and therefore no reaction will occur.

The optimum pH will be 7, and very high pH (pH 10) will denature the enzymes.

The enzymes are reusable as long as they are not denatured.

Materials & Procedure

Peel a fresh potato tuber and cut the tissue into small cubes.

Weigh out 50 grams of tissue.

Place the tissue, 50 mL of cold distilled water, and a small amount of crushed ice in a prechilled blender.

Homogenize for 30 seconds at high speed.

Filter the potato extract using cheesecloth.

Pour the filtrate into a 100 mL graduated bylinder and add cold distilled water to bring up the final volume to 100 mL.

Label eight 50 mL beakers as follows: 100 units/mL, 80 units/mL, 75 units/mL, 60 units/mL, 50 units/mL, 25 units/mL, 10 units/mL, 0 units/mL.

Prepare 40 mL of enzyme for each of the above concentrations in the following ratio of enzyme:distilled water - 40:0, 32:8, 30:10, 24:16, 20:10, 10:30, 4:36, and 0:40.

Using forceps, immerse a 2.1cm filter paper disc into the prepared catalase solution for 5 seconds.

Remove the disc and drain for 10 seconds on a paper towel.

Place the disc at the bottom of the first substrate solution. The oxygen produced from the breakdown of the hydrogen peroxide by catalase becomes trapped in the fibers of the disc, thereby causing the disc to float to the surface of the solution

Measure (using a ...