A convenient protein is gelatine. This is derived from animals and is used by Kodak, Ilford, Agfa, Fuji and other companies when they make photographic film. The plastic backing has a thin layer of gelatine containing silver salts spread on it. The gelatine layer is called “Emulation”. On unused film it looks dark. The protease enzyme can digest the gelatine by the protease enzyme pepsin leaving silver salts behind. As they are no longer supported by the gelatine they will fall to the bottom of the test tube and the film that was in contact with the enzyme will become clear.
Preliminary work
“The affect of different temperatures on trypsim activity”, this was an experiment done a week prior to the actual experiment. Trypsim is a protein-digesting enzyme produced by the pancreas. In the investigation the enzyme is used to digest casein, a white protein contained in powdered milk. We put 5cm3 of milk in a test tube and 5cm3 of trypsim. From heating 20c, 30c, 40c, 50c, 60c, 70c, from this I can conclude that the best temperature for enzymes to work is somewhere between 30c and 40cbecause by the time that you reach 50c some of the enzymes had died.
Prediction
I predict that the speediest reaction will be with the experiment at 50c even though the preliminary work does not tally with this, I think that the reaction should be very quick and should be over by the time that some of the enzymes start to not function properly.
Method
To do the experiment 2ml of pepsin will be heated up to the temperatures of 10c, 20c, and 50c then a strip of photo film, and time using the stop watch to time how long it takes for the gelatine to be digested. I will be able to tell this when the film becomes see through. The experiment is then repeated to make sure that all the results are accurate. This way I will be able to tell whether or not I have conducted a good or a bad experiment
Results time in seconds
Conclusion
What I learnt is that temperature is very important when it comes to the reaction of enzymes. When the solution is heated the particles vibrate more quickly and eat at the film but if the temperature is too high the enzymes will get killed. Enzymes work best at your body temperature around 37 degrees Celsius. Another thing that can affect enzymes is the ph levels, enzymes work best at levels between 6 and 8 which is the same sort of ph level in your stomach.
Evaluation
When looking at my results I didn’t think that they were very reliable or accurate and I think that I went wrong somewhere because all of my results were anomalous. If I had had longer time to do more experiments and had better equipment my results could and probably would have been a lot more accurate and because of this I personally do not think that my results are very reliable.
Darren tait 10.4
