Gel filtration chromatography
Proteins can be separated and purified based on size, charge and affinity. One way to separate proteins is the gel filtration chromatography, which is a type of column chromatography. Another name for gel filtration chromatography is molecular exclusion chromatography.
The method to conduct the gel filtration chromatography is, firstly load the protein sample onto the top of the column which consists of porous beads. These porous beads have a diameter of approximately 0.1 mm and are composed of insoluble and highly hydrated polymer, for example, polyacrylamide or carbohydrates such as dextran or agarose. To prepare these beads commercially, Sepharose, Biogel and Sephadex are used commonly. Only smaller proteins can pass through the beads while large proteins are unable to. Smaller proteins will be located in the aqueous solution both inside the beads and between the beads, whereas larger proteins are distributed in the solution between the beads. As a result, smaller proteins have to go through a long pathway and travel much slower, where larger proteins will move down the column at a much faster speed.
- ↑ Jeremy M. Berg, John L. Tymoczko, Lubert Stryer. Biochemistry. Chapter 3 Exploring Proteins and Proteomes P.71. Seventh edition. U.S.A.; W.H. Freeman and Company; 2012