Question

Describe how the GST tag could be utilized to purify the fusion protein DHFR from a cell lysate.

Answer 1

# Recombinant human DHFR (Dihydro folate reductase) protein fused to GST-tag can be purified by GSH- sepharose.

pGEX E.coli expression vector encodes a molecule N-terminal glutathione S-transferase followed by a protease cleavage site in it. Proteins fused with GST can be purified by affinity chromatography on commercially available glutathione sepharose from protein lysate.

Therefore, recombinant DHFR with GST will be purified by affinity chromatography and the protein of interest will be separated from GST later by using protease enzyme.