A. Ion-exchange chromatograph separates proteins based upon the sign and magnitude of their charge at a given PH

B. Two-dimensional gel electrophoresis separates proteins first on the basis of their PI values and second on their charge to mass ratio using SDS

C. Affinity chromatograph exploits the selectivity of protein-ligand interactions to isolate a specific protein from a complex mixture

D. Many recombinant proteins are expressed with an additional domain fused to their N-or C-terminals. One common component of these fusion domains is a ligand binding site designed expressly to facilitate purification by affinity chromatography

E. Tandem mass spectrometry can analyze peptides derived from complex protein mixtures without their prior separation