Protein Purification by Ion Exchange Chromatography (CAT#: STEM-MB-1295-LGZ)

Introduction

Ion exchange chromatography (IEX) is a chromatographic separation method essentially based on the net charge of the protein, and is generally used to follow deamidation and succinimide formation. There are two types of IEX, cation exchange and anion exchange chromatography. At buffer pH values above this IP, the protein is negatively charged (anionic); at pH values below that, the protein is positively charged (cationic).<br />All proteins exhibit a net charge that depends on the amino acid composition of the protein and any covalently attached modifications. The net charge of a protein is influenced by the pH of the solvent that it is dissolved in, as solvents exchange hydrogen ions with proteins. Typically, binding of a protein to IEX must be determined by trial and error, using solvents with a range of pH values, to determine the optimum pH for protein retention. A solvent pH that is about one pH unit away from the pI is usually sufficient for protein binding.