What steps does a protein purification process comprise?
A protein purification method can be structured into the capture, intermediate purification, and polishing (CIPP) model.
- In the initial capture stage, sample preparation is followed by isolation and concentration of the target protein.
- During intermediate purification, bulk contaminants are removed.
- In the final polishing step, the most difficult impurities, such as for example aggregates of the target protein, are removed.
What factors determine the protein purification strategy?
The purity requirement differs dramatically between usages of the purified protein. Also the amount of protein required for different use varies greatly, from picograms to kilograms or even tons.
In a research setting, purity requirements are often modest and only a chromatography capture step might be required.
Also when purity demands are higher, the capture step can be sufficiently efficient to be immediately followed by a final polishing step.
Addition of chromatography steps will increase purity at the cost of decreased yield of active protein.