Question

How to avoid proteolysis in purified protease samples?

Answer 1

I am currently in the process of purifying a His-tagged protein. I use a Nickel column and then an ion exchange column to further get rid of other proteins. I have been pretty successful, but I am still getting a degraded band right underneath my protein. I use a Protease Inhibitor Cocktail Tablet from Roche and perform all steps at 4 degrees.