Question

Why is ammonium sulphate added slowly in protein purification

Answer 1

Ammonium sulphate may be added as a solid or as a saturated solution (4.01M). It is preferable to add the ammonium sulphate as a 100 percentage saturated solution and our small sample size allows the use of this method for the first addition. However, in order to prevent significant dilution of the sample, addition of solid will be used in the second precipitation. It is important to add the salt slowly to the solutions to avoid creating localised areas of higher concentration that desired.