How a protein can be purified by affinity chromatography

A protein is constructed by peptide sequences, and each peptide will have a specific shape which will fit appropriately on the site of affinity column.

The most common column to purify protein is Blue sepharose. It is made from~2 μmole Cibacron Blue F3G-A/ml drained medium. The process can be performed in one step. The protein of interest will be retained by the affinity column then eluted by appropriate compound adding to the eluent.
Proteins also can be separated based on the pI value, by anion exchange chromatography.
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Packing sepharose column