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ion exchange chromatography

^ http://purl.obolibrary.org/obo/MI_0226


Stable complexes and their component proteins can be separated on the basis of their net charge by ion-exchange chromatography. If a protein has a net positive charge at pH 7, it will usually bind to a column of beads containing carboxylate groups, and can then be eluted by increasing the concentration of sodium chloride or another salt in the eluting buffer by competition of sodium ions with positively charged groups on the protein for binding to the column. Protein that have a low density of net positive charge will tend to emerge first, followed by those having a higher charge density. Positively charged complexes or proteins (cationic proteins) can be separated on negatively charged carboxymethyl-cellulose (CM-cellulose) columns. Conversely, negatively charged complexes or proteins (anionic proteins) can be separated by chromatography on positively charged diethylaminoethyl-cellulose (DEAE-cellulose) columns. [ http://www.ncbi.nlm.nih.gov/pubmed/14755292 ]

Synonyms: ion exchange chrom, IEC

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