What is the role of diethylaminoethyl (DEAE) in ion exchange chromatography?

In ion exchange chromatography, diethylaminoethyl (DEAE) serves as a positively charged anion-exchange resin. Its role is primarily to bind negatively charged molecules, such as negatively charged amino acids, peptides, or proteins from a sample mixture. The positive charges on DEAE interact with the negative charges on these target molecules based on their charge characteristics at a given pH. This interaction enables the separation of proteins based on their charge, which is crucial for purifying specific proteins from a heterogeneous mixture. Additionally, the bound proteins can later be eluted from the column by changing the conditions, such as increasing the salt concentration or altering the pH, which affects the interaction between the DEAE and the proteins.

Understanding that DEAE functions specifically to attract negatively charged species clarifies its purpose in the context of ion exchange chromatography.