Investigation on Protein Denaturation
By y.c.pong
Introduction:
When you heat an egg, the egg white clump together and turned white. It is because the protein in egg white undergoes denaturation, the cross linkage(the hydrogen bonds, ionic bonds and disulphride bonds) which maintain the protein shape destructed, so protein lose its tertiary conformation. This denaturing process is very important, because before protein can be used in digestion they must be unfolded.
Part A: denaturation of egg white
Aim:
To examine the factors on the effect of denaturation of egg white.
Principle:
As protein denaturation can be cause by several factors such as temperature, pH, salt concentration. In this experiment, we are examining how these factors affect the denaturation of protein. We use egg white, which is actually a solution of protein in water in this experiment. After the egg white had been dilute, the egg white solution can be put in 60⁰C and 80⁰C water bath to test for how temperature affects denaturation. It can be record by the time need for the first change of appearance. To find out how pH of affect denaturation, we can add dropwise the actetic acid to the egg white solution. Beside, the NaCl can also be add dropwise to egg white, to test for how salt concentration cause denaturation. Count the number of drop of solution added for an appearance change to occur.
Observation:
|60 ⁰C water bath |After 15 minutes, a pale yellow |
| |semi-solid formed |
|80 ⁰C water bath |After 2 minutes 30 seconds, a white jelly|
| |like solid formed. |
|1M acetic acid |After 10 drops of acid added, the |
| |solution become pale yellow and clumping |
| |of egg white occurs |
|5M NaCl
Introduction:
When you heat an egg, the egg white clump together and turned white. It is because the protein in egg white undergoes denaturation, the cross linkage(the hydrogen bonds, ionic bonds and disulphride bonds) which maintain the protein shape destructed, so protein lose its tertiary conformation. This denaturing process is very important, because before protein can be used in digestion they must be unfolded.
Part A: denaturation of egg white
Aim:
To examine the factors on the effect of denaturation of egg white.
Principle:
As protein denaturation can be cause by several factors such as temperature, pH, salt concentration. In this experiment, we are examining how these factors affect the denaturation of protein. We use egg white, which is actually a solution of protein in water in this experiment. After the egg white had been dilute, the egg white solution can be put in 60⁰C and 80⁰C water bath to test for how temperature affects denaturation. It can be record by the time need for the first change of appearance. To find out how pH of affect denaturation, we can add dropwise the actetic acid to the egg white solution. Beside, the NaCl can also be add dropwise to egg white, to test for how salt concentration cause denaturation. Count the number of drop of solution added for an appearance change to occur.
Observation:
|60 ⁰C water bath |After 15 minutes, a pale yellow |
| |semi-solid formed |
|80 ⁰C water bath |After 2 minutes 30 seconds, a white jelly|
| |like solid formed. |
|1M acetic acid |After 10 drops of acid added, the |
| |solution become pale yellow and clumping |
| |of egg white occurs |
|5M NaCl