BACKGROUND GST is commonly used to create fusion proteins.1 The tag has the size of 220 amino acids (roughly 26 KDa), which, compared to other tags like the myc- or the FLAG-tag, is quite big. It is fused to the N-terminus of a protein. However, many commercially-available sources of GST-tagged plasmids include a thrombin domain for cleavage of the GST tag during protein purification.
A GST-tag is often used to separate and purify as well as confirm expression of proteins that contain the GST-fusion. GST-fusion proteins can be produced in Escherichia coli, as recombinant proteins. The GST part binds its substrate, glutathione. Agarose beads can be coated with glutathione, and such glutathione-Agarose beads bind GST-proteins. These beads are then washed, to remove contaminating bacterial proteins. Adding free glutathione to beads that bind purified GST-proteins will release the GST-protein in solution. GST-tag antibody is a useful tool for confirming protein expression, localization of expressed proteins in cells, as well as affinity-binding of GST-tagged proteins.2
1. Scheich, C. et al: BMC Biotechnol. 3:12, 2003 2. Nojima, H. et al: J. Biol. Chem. 278:15461-4, 2003
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Purified recombinant GST-tag expressed in E. coli.
Species & predicted
reactivity ( ):
Weight of protein:
26 kDa (GST-tag)
Detects endogenous proteins without cross-reactivity with other family members.
Store at -20°C, 4°C for frequent use. Avoid repeated freeze-thaw cycles.
*Optimal working dilutions must be determined by end user.