Who would like some denatured egg albumin for breakfast?
Materials
- Bunsen burners - NaCl
- Mineral Oil - Ice Cubes - 1% AgNO3
- Acetone
- Methanol - Strong HCl - Strong Base
- Beakers
- Test Tubes - Eggs
- Electronic pH meter
- Infrared thermometer
Background:
Proteins are large biological molecules that are made up of a bunch of small amino acids that are
all connected one after the other in a string. The amino acids are stuck together by connections
made between the hydrogen atoms (these are called hydrogen bonds) and by connections made
between sulphur atoms (these are called disulphide bonds). When the bonds between the
hydrogen atoms are broken we say that the protein has been denatured. Since the amino acids are
not connected together in a string any longer the shape of the protein changes. When the shape of
a protein changes, it’s chemical and physical properties change and it isn’t able to function the
way that it normally does.
Objective:
To use the equipment and eggs that have been provided, as well as any other substance in the lab
that Mr. Bausch allows, to determine SEVEN ways that we can denature a protein. If you have
identified something that denatures a protein, and the cause of its effect is not obvious, such as it
being strong hydrochloric acid, you must provide ONE generalized characteristic of the substance
which might have caused the denaturation. For example, if you test Mr. Clean and it denatures
the protein, you should test the pH of the Mr. Clean as well.
What protein are we using and how will I know if it has been denatured?
Egg whites (not the yolks) contain a protein called albumin. On at least one morning in your
lives you’ve each most likely witnessed the chemical change that occurs when egg albumin is
denatured. Every time that egg albumin is denatured you will observe the same chemical
changes.
Need help writing a discussion? Use the information and reference
below.
Ophardt, C. (2003). Denaturation of Proteins. Virtual Chembook. Retrieved (2010, January 11)
from http://www.elmhurst.edu/~chm/vchembook/568denaturation.html