Question

Gel filtration chromatography is frequently used to remove salts such as NaCl from a protein preparation. Why?

Answer 1

• Gel filtration used frequently to remove salts from the sample, due to its ability to separate "small" from "large" components.

Other possibilities:

Compared to dialysis, gel filtration has the advantage of speed (a few minutes vs. hours for dialysis), which is necessary in certain experimental situations. For example, reduced peptides must be desalted quickly to remove reductant and initiate subsequent sulfhydryl-reaction procedures before oxidation back to disulfides occurs

To analyze the protein without the salts that were used to isolate the protein from the original sample.

To subject the protein sample to gel electrophoresis or other chromatography techniques, or see what the activity of the protein is or if it changes without the excess NaCl around.