Why do scientists want to purify proteins?
Scientists in biotechnology must face the challenge of protein purification regularly. But
the question arises, why do scientists need to take the pain? In a research environment,
proteins must be purified in order to determine their structure and study their
biochemical properties. In industrial settings, proteins are purified on a larger scale in
order to be sold as products such as drugs, vaccines, diagnostic tools or food
additives, which are the daily requirement of human beings. The vaccines, drugs,
enzymes, certain food additives that we take daily are proteins, which should be purified
in order to use them efficiently. We cannot rely on mixture of proteins as different
proteins have different applications, hence a single protein needs to be purified to work
efficiently and increase the reliability.
Also, since proteins are essential to nearly every living process, scientists want to learn
everything they can about them.
How does size exclusion chromatography works?
Size exclusion chromatography or gel filtration chromatography works on the principle
of separation of proteins on the basis of their size.
The column is packed with a matrix of fine porous
beads. It works somewhat like a sieve, but in
reverse. The beads have in them very small holes.
As the protein solution is poured on the column,
small molecules enter the pores in the beads. Larger
molecules are excluded from the holes, and pass
quickly between the beads.
These larger molecules are eluted first. The smaller
molecules have a longer path to travel, as they get
stuck over and over again in the maze of pores
running from bead to bead. These smaller molecules,
therefore, take longer to make their way through the
column and are eluted last.