Question

What is the differences between GST pull down assay and IP? I wanna know at least 4~5 things.

Answer 1

Ans. GST pull down assays involves affinity purification of one or several unknown proteins from a biological sample using a GST-tagged bait protein. The basic principle is that the GST-tagged bait protein binds to its partner, and the resulting complex is captured on beads with immobilized glutathione.

GST pull down experiments are used to identify interactions between a probe protein and unknown targets and to confirm suspected interactions between a probe protein and a known protein. The probe protein is a GST fusion, whose coding sequence is cloned into an isopropyl --D-thiogalactoside(IPTG)-inducible expression vector. This fusion protein is expressed in bacteria and purified by affinity chromatography on glutathione -agarose beads.

Immunoprecipitation (IP) is the technique of precipitating a protein antigen out of solution using an antibody that specifically binds to that particular protein. This process can be used to isolate and concentrate a particular protein from a sample containing many thousands of different proteins.

Immunoprecipitation requires that the antibody be coupled to a solid substrate at some point in the procedure.