Question

1a. Give a full molecular description rationalising why protein requires a relatively high concentration of ammonium sulphate for it to precipitate .

1b.Explain at a molecular level the difference between modes of action of (i) a lyotropic salt, and (ii) a chaotropic salt for a protein molecule  

Answer 1

1a. Amonium sulphate is generally used to increase the stability if protein and form amonium and sulphate ions when introduced into the solvent by salting in but in higher conc. It causes precipitation of protein by salting out.

1b. Lyotropic salts are salts which can be used to increase stability by the process of salting in. These may be anionic or cationic. Anions are more efficient in providing stability than cations.

Chaotrophic salts are those salt which affact the satbility by disturbing the H-bonds in proteins.