globular protein solubility in water?

[forchina]

Hi
Is this correct - globular proteins dissolve in water because hydrophilic r groups are attracted to water. Thus these parts of the protein are dissolved by water and so this disrupts the entire structure of protein, breaking it apart and making it soluble?

I wrote this in a test and im not entirely sure it's right. It was out of 2 marks so hopefully i get at least 1 out of 2.

Thanks.

[psyxwar]

That's pretty much right (the hydrophilic amino acids are exposed to water whereas the hydrophobic amino acids are not due to hydrophobic interactions), but your second sentence is wrong -- they aren't broken apart and made soluble, nor is the entire structure disrupted. Only salts are broken down into their constituent parts when dissolved.

[Scooby]

Individual protein molecules are surrounded by water. Basically, these protein molecules have a greater affinity for the water molecules (due to the hydrophilic R groups at their surface) than other protein molecules.

When you dissolve a substance, you're not breaking apart the constituent molecules in any way. You're disrupting the interaction between the constituent molecules of the substance; you're not actually affecting the structure of each individual molecule. They're just more attracted to the solvent than other molecules which previously made up that substance