Ion exchange chromatography is used to separate proteins fro

Ion exchange chromatography is used to separate proteins from each other. The basis of this separation is:

a) different motilities in an electrical field

b) differing size of the proteins

c) Differing solubility between a moving and stationary front

d) differeing ionic charges

Solution

The correct choice is option d. Proteins are separated in a column consisting of a matrix bearing a specific charge. Proteins that have a cognate charge (opposite and most equal in magnitude) show greatest affinity for the column and are bound to it. All other proteins pass through the column. Later, the bound protein can be washed out using a buffer that neutralizes the charge on the protein so that it cannot bind the column any more.