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Enzyme concentration and activity

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Enzyme Concentration and Activity In this experiment, I will investigate the effect of enzyme concentration on the rate of the reaction where protein is broken down by protease enzymes. If the enzyme concentration is raised, I predict that the rate of reaction will increase. This is due to more enzyme molecules being present, so a greater chance of collision with the protein chains. Therefore there will be more collisions in a given time, so the protein will be broken down more quickly. However, at a certain point, this correlation with level off due to other limiting factors. The independent variable is the concentration of protease solution. The dependant variable is the time taken for the whole sample of cooked egg white to turn clear. Here is a table of the variables I will keep controlled. Factor How I will prevent it How it would affect my results How the error would be visible in my results What kind of error Temperature Keep all enzyme solutions at the same temperature Extra heat energy will give all of the particles more energy, so the reaction will speed up. ...read more.


the egg white Petri dishes To perform the experiment in Dropping pipettes To transfer the enzyme solution Distilled water To use as a control and to dilute the enzyme solution 100cm3 acidified protease solution Source of enzyme 100cm3 beakers To hold the enzyme solution 25cm3 measuring cylinders To measure the solution and water Stop watches To time the reaction Knife To cut the cooked egg white Method 1. Pour the egg white to a depth of 0.5cm in a Petri dish and microwave on full power for 2 minutes (or until cooked). 2. Cut the egg white into 2cm x 2cm squares and place each in a clean Petri dish. Allow to cool to room temperature (as the temperature of the freshly cooked egg could denature the enzyme). 3. Use the distilled water to make the protease solution up to concentrations of 0.1%, 0.2%, 0.3%, 0.4% and 0.5%. 4. Pour each concentration into a labelled beaker. 5. Using a dropping pipette, add 3 drops of distilled water to one piece of egg white, and time how long it takes to turn clear. Repeat twice. ...read more.


Still, nothing was observed. This was probably due to a faulty batch of enzymes, as we extended the time of the experiment and increased the temperature to eliminate these as limiting factors. If the experiment had worked as predicted, I would expect the graph of the results to look like this: Conclusions The experiment didn't work as predicted, even when we increased the time and temperature. The colorimeter was calibrated correctly using an opaque blank (giving a 0% transmission) and a clear blank (giving 100% transmission). There was a �1% error in the measurements of the milk powder solution and the enzyme solution. There was a �0.1 error in the percentage transmission reading. There are no anomalous results, as all enzyme solutions gave a 0% transmission reading at all times. I would repeat this experiment with a new batch of enzymes, keeping it at 37�C for the whole experiment. I may try higher concentrations of enzyme solution if the new batch showed no visible results either. ?? ?? ?? ?? Although I planned an experiment using egg, we carried out an experiment using milk powder solution. The prediction applies for both experiments. ...read more.

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