Question

what was the reason to add buffer C with 0.05 M KCl to the resin? What was the reason to add Buffer C with 0.2 M KCl to the resin ?

Answer 1

The resins are used for separation of proteins.

For separation of proteins we need KCl which maintains the stability of charges on proteins in the ions exchange resin.

Now we also use buffer alonwith KCl as

a) Buffer prevents damage to protein

b) the buffered KCl is used to avoid proteins that are unwanted for binding to the resin (unspecifically).

c) They are also good to give stability to the charges of proteins which are else highly sensitive to pH depending upon isoelectric point.