Ion Exchange Chromatography

Abstract

Ion exchange chromatography is a method for separating complex mixtures on the basis of differing tendencies of individual charged molecules (ions) to exchange with like‐charged species bound by electrostatic attraction to groups immobilized on a stationary phase. It is especially suitable for purification of proteins as their net charge may be altered by varying pH.

Keywords: bioseparation; chromatography; displacers; ion exchange; perfusion; protein; membrane

Figure 1.

Basis of anion exchange chromatography. Proteins with differing charge are represented as blue circles. The positively‐charged ion exchange group immobilized on the stationary phase is charged with Cl counterions. (a) Protein with net negative charge exchanges with Cl while that with a net positive charge simply passes through the stationary phase without binding. (b) Negatively‐charged protein is held on the ion exchange group by electrostatic attraction. (c) The protein is eluted by exchange with Cl ions provided by an NaCl gradient.

Figure 2.

Purification of acetolactate decarboxylase (ALD) by anion exchange chromatography on a column of POROS PI perfusive packing. Proteins from Leuconostoc lactis NCW1 bound to the column at pH 7.0 were selectively eluted with an NaCl gradient (dashed line). Several peaks of protein were deteced by monitoring the absorbance at 280 nm (A280). ALD activity (red triangles) is expressed as μmol L−1 min−1 of the decarboxylation product, acetoin, determined spectrophotometrically at 525 nm. It was found to elute in a single peak that was pure by the criterion of SDS polyacrylamide gel electrophoresis.

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References

Charcosset C (1998) Purification of proteins by membrane chromatography. Journal of Chemical Technology and Biotechnology 71(2): 95–110.

Cramer SM (1991) Displacement chromatography. Nature 351(6323): 251–252.

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Regnier FE (1991) Perfusion chromatography. Nature 350(6319): 634–635.

Sheehan D and Fitzgerald R (1998) Ion exchange chromatography. In: Rapley R and Walker JM (eds) Molecular Biomethods Handbook, pp. 445–449. Totowa, NJ: Humana Press.

Further Reading

Abrams IM and Millar JR (1997) A history of the origin and development of macroporous ion‐exchange resins. Reactive and Functional Polymers 35(1–2): 7–22.

Kaufmann M (1997) Unstable proteins: how to subject them to chromatographic separations for purification procedures. Journal of Chromatography B 699(1–2): 347–369.

Leonard M (1997) New packing materials for protein chromatography. Journal of Chromatography B 699: 3–27.

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How to Cite close
Sheehan, David, and O'Sullivan, Siobhan(Apr 2001) Ion Exchange Chromatography. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0002677]