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Enzyme Lab Report

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Enzyme Lab Report


The purpose of this lab was to measure the extent of enzyme reaction on given substrates by means of color change. The reaction followed is given below:



Pyrocatechol Hydroxyquinone

Oxidation/Reduction Pink „і Brown

E+S + [ES] = E+P

Enzyme Reaction

Hypothesis: If there is an increase in enzyme concentration, an increase in reaction temperature, or an increase in buffer pH, then greater intensity in a given reaction will be experienced, resulting in greater manipulation of the final substrate product; measured by the extent of substrate color change.

Greater manipulation of substrate when introduced into stronger, less diluted enzyme, higher buffer pH, and/or higher temperature is expected.

We know that color change is an effective method of measuring chemical activity within a given reaction. The stronger, more drastic the color change, the more chemical activity present. For this experiment we are concerned with enzyme activity. Knowing that enzymes act as catalysts within a chemical reaction, the extent of color change present should shed light into the character of the given enzyme.


Experiment One: As enzyme concentration increases, color change from pink to brown increases. Therefore, we know that the rate and the extent of the reaction increases, (as measured by color change) due to greater enzyme activity.

Graph One Explains:

Experiment Two: As enzyme concentration increases, an increase in color change is seen. However, there appeared a saturation point. Color change did not increase from 1:1 ratio of dilution to Ў§StockЎЁ enzyme with no dilution due to reaching a saturation point at which the enzyme reached its full catalytic potential.

Graph Two Explains:

Experiment Three: As deviation from a neutral pH of 7.0 within the buffer is presented, the rate and completion of the given reaction was hindered. Greatest color change, hence greatest enzyme activity is seen at a neutral pH of 7.0, concerning the buffer solution. Increase and decrease in pH within the buffer seems to put strain on the enzymeЎ¦s ability to act as a catalyst and hence decreased the rate and completeness of the reaction.

Graph Three Explains:


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