title: Using ion exchange chromatography to purify a recombinantly expressed protein.
abstract: Ion exchange chromatography (IEX) separates molecules by their surface charge, a property that can vary vastly between different proteins. There are two types of IEX, cation exhange and anion exchange chromatography. The protocol that follows was designed by the authors for anion exchange chromatography of a recombinantly expressed protein having a pI of 4.9 and containing two cysteine residues and one tryptophan residue, using an FPLC system. Prior to anion exchange, the protein had been salted out using ammonium sulfate precipitation and partially purified via hydrophobic interaction chromatography (see Salting out of proteins using ammonium sulfate precipitation and Use and Application of Hydrophobic Interaction Chromatography for Protein Purification). Slight modifications to this protocol may be made to accommodate both the protein of interest and the availability of equipment.
authors.affiliation: Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Krisna C
authors.initials: KC
authors.lastname: Duong-Ly
authors.affiliation: Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA. Electronic address: gabelli@jhmi.edu.
authors.forename: Sandra B
authors.initials: SB
authors.lastname: Gabelli
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D011232:Chemical Precipitation; D002852:Chromatography, Ion Exchange / Q000295:instrumentation / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D011994:Recombinant Proteins; D000645:Ammonium Sulfate
keywords: Carboxymethyl (CM); Diethylaminoethyl (DEAE); FPLC system; Ion exchange chromatography (IEX); Quaternary aminoethyl (QAE); Quaternary anion (Q); Sulfopropyl (SP)