AboutRalph Salier-Hellendag Expertise Science Fair Judge for many years and experience with robotics, biology, chemistry, industrial processes, metalurgy and metal forming.
Experience Science Fair Judge for many years and have helped several students get to state level competition. Most recently 2 of my students received state level awards and one went on to the nationals in Washington DC.
Education/Credentials BA Archaeology - Anthropology
MA Business Anthropology
Question QUESTION: I am doing an experiment to test the effect of different pH levels on the digestion of proteins. The original project that I got the idea from did not have any detailed procedures, so I changed/added on to them and I was hoping if you could see and tell me if the following procedure will work- and if not what I should do to make it work. Thank you very much and please reply as soon as possible!
1.In 100 mL of different pH level BUFFER SOLUTIONS (levels of 2, 4, 7, 10, and 12), add 0.2 grams of powdered albumin.
2.Stir the albumin/buffer solution to form the albumin-buffer solution.
3.Pour 5 mL of the solution in to the test tube.
4.After waiting for 10 minutes, add 2.5 mL of biuret solution.
5.Mix by rotating the test tubes in your palms for 20 seconds.
6.Wait 30 minutes for the color to fully develop.
7.After waiting 30 minutes, test the absorption of light using spectrophotometer to see the range of protein left over in the test tubes.
Would putting powered albumin into different pH level buffer solutions actually digest the proteins down? My science teachers have said it SHOULD work, but they are not 100% sure because they have not done/seen the experiment for themselves.
ANSWER: Hmm, I'm not sure. I would suggest that you do something very simple like use gelatin. Pour gelatin in test tubes and let it harden. Add your different pH solutions. Let sit for X time. Measure the amount of solid gelatin over various time frames.
Since gelatin is protein this should be an easier way to measure the affects of pH on protein.
---------- FOLLOW-UP ----------
QUESTION: I am coming back to this project and I have another question if could kindly answer it again for me. When using gelatin, what do you mean let it harden? Do i have to add water and then let it harden or can I just add gelatin powder with the buffer solutions and then let it sit for X time?
ANOTHER QUESTION, when testing with the spectrophotometer, should just the distilled water be my blank or do i need to add the biuret solution to the water as well?? thank you!!
Answer Hi S,
Yes, make the gelatin using hot water and then pour this into each test tube. Allow it to harden. Then add the buffer solutions. You can then watch how long it takes for each buffer solution to break down the gelatin. Or if you have a set time frame, you can measure how much "solid" gelatin is left over.
#2 if you are using distilled water run it twice. First to ensure that it is distilled and that you don't have any stray peaks and secondly, from the same source add the buret solution and recheck. This way you have both.
