Hi all,

 

God has created human beings in complex and complicated ways that It is difficult to imagine anything like it. If i am not mistaken, hair and skin of humans are tertiary proteins. They are insoluble so they dont dissolve in water when we go for a swin or take a bath. I want to ask why is this! My take on this is that it has a coiled structure and from the inside are the intermolecular forces, hydrogen bonding, disulphide bonds and others. From the outside there are no hydrogen bonds which is why its insoluble.

 

Why do you people think!

I don't know much about protiens in the tertiary structure, but i do know why i think!

 

I enjoy thinking, it makes me happy

hair and skin have keratin and collagen protein...

 

both are insoluble fibres... they are nanometers thin but very long...

 

fibrous proteins rarely disolve...

 

but globular proteins, like insulin, are globs (i.e. balls) and the vast majority dissolve in water...

yes I know, however I wanted to ask was it beacuse of the coiled structuer?

What you are refering to is at least in part due to hydrophobic and hydrophilic properties which help to determine protein shape. Hydrophillic proteins are generally dissolved in water at the proper pH and relatively hydrophobic proteins not so much.

Proteins have hydrophobic (water loving) and hydrophobic (water disliking) character in different areas and this helps them form complex structures.

Tertiary just means that they have a high or complex degree of structure (beyond primary and secondary structure). Coiling (alpha or beta sheets or coils) can be considered a tertiary type structure. Hydrophilic, hydrophobic, attractive and repulsive Van Der Wals, London forces, salt bridges, ionic interactions, hydrogen bonding, and other interactions serve to hold the tertiary structure together. Also, the proteins do not "dissolve" in the water in part because of the shear magnitude of their size. They are large biopolymers, the basic or primary structure of which is held together by covalent bonds which do not dissociate in water. These relatively large structures then associate to form HUGE structures like for example, hair.

Solubility can be enhanced or decreased with various ions, surfactants, pH, or other things that can be added to the water or buffer which alter the intramolecular and intermolecular interactions I have listed above.