Science Buddies: "Ask an Expert"

Hi!
I am doing a science project on the denaturation of the proteins casein, albumen, and keratin. I'm doing an experiment where I heat up hair, an egg, and milk to see what temperature they denature at. I also need to do research questions on the topic of protein denaturation. So far, I have these:

What happens when a protein denatures?
Do all proteins denature at the same temperature?
What temperature does albumen denature at?
What temperature does keratin denature at?
What temperature does casein denature at?
Why might proteins denature at different temperatures?

I'm having some trouble coming up with other questions that are at my grade level (9). I would really appreciate any help coming up with some. Thank you!

Hi,

I guess my first question would have to be how will you decide that a protein has been denatured? When I fry an egg I can see that the clear part turns white and the yoke gets firm so probably the proteins have been heat-denatured. But that's not really very scientific.

How do scientists define denaturation in published papers? The amino acids in a protein and the bonds they make with one another are what holds a protein together and when it is heated, the increased temperature causes some of these bonds to break and that is one part of the denaturation process.

There is one very strong bond that holds some proteins together and that is called a disulfide bridge. it is formed between two sulfur atoms on adjacent amino acids, like this ---S--S--
You should look this up and read about it because disulfide bonds are one of the things that stabilize a protein and make it resistant to denaturation.

Proteins are held together by many bonds, not just a few. One bond may not be that strong by itself, but when there are dozens, they can add up to make the protein quite resistant to denaturation.

If you look on the NCBI website for protein analysis apps, i think there is one for denaturation: https://www.ncbi.nlm.nih.gov/protein

I hope I have answered some of your questions--and probably caused 10 more! Proteins are really amazing molecules. They do all the chemical reactions in your body without you having to even think about it--and they get them right! Usually. When the protein is defective because of a mutation int eh DNA that codes for it, then you can have serious health problems. The new gene-editing method called CRISPR may eventually allow gene surgeons to correct defects like this and give people hope for a normal life.

Good luck!

Sybee