Question

Suggest the best method of chromatography to separate each of the following pairs:

a. protein from a salt

b. peptide fragments obtained after protease digestion of a protein from the intact protein

c. two isozymes differing by one arginine (positively charged) residue

d. antibodies that bind to two different antigens

e. two peptides with slightly different amounts of hydrophobic amino acids

f. DNA from protein

So far I think C is Ion exchange, D is affinity, and E is hydrophobic interaction. Correct me if I'm wrong here :)

Answer 1

a) Salting out will elute your protein from the salt

b) SDS PAGE, HPLC or ion exchange chromatography

c) Ion exhange chromatography based on the pI of the protein.

D) antibodies that bind to two different antigens by affinity chromatography

e) Hydrophobic interaction chromatography seperates protiens based on their exposed hydrophobic aminoacids

f)DNA from protein using silica coloum. The sample is treated with proteases first to remove proteins