Elabscience Recommendations

Myc-tag has been successfully applied to Western Blot (WB), Immune Precipitation (IP), and Immunofluorescence (IF), which are used for the detection of recombinant protein expression in bacterium, yeasts, insect cells and mammalian cells. Myc recombinant proteins can be purified by coupling Myc-tag antibody to diethylsulfone activated agarose. Myc-tag can be either on C terminal or N terminal. Due to the low pH elution condition which often reduces the activity of the protein, Myc-tag system is mainly used for testing but not for purification.

His-tag is a short peptide consist of six histidine (His-His-His-His- His-His), which is specially used for the absorption and purification of recombinant proteins. With small molecular weight and easy separation and purification process, His-tag has a distinct advantage over other labels, which makes it the most widely used fusion tag. An efficient detection and purification system based on fusion protein can be established by His-tag. His-tag antibodies can be used to detect the expression, intracellular localization, and qualitative or quantitative test of His-fused protein.

HA-tag can simplify the protein purification process, control the fixed space orientation of protein, visualize the biological events in vivo, increase production, solubility and stability of the recombinant proteins. The HA-tag system uses an HA (influenza hemagglutinin epitope: YPYDVPDYA) peptide to fuse to the target protein. HA-tag can be either on C terminal or N terminal. This system has been widely used in many kinds of cell types, corresponding HA-tag antibodies are as well widely used. HA-tag antibodies can specifically identify the fusion protein with HA-tag on C terminal or N terminal.

The Flag-tag system uses a short hydrophilic peptide with eight amino acids（DYKDDDDK）to fuse to C terminal or N terminal of the target protein. It has been widely used in many kinds of cell types, including bacterium, yeasts and mammalian cells, corresponding HA-tag antibodies are as well widely used. As the purification condition of the Flag-tag system is non- denatured, all active fusion proteins can be purified by it. Flag-tag can be removed by adding enterokinase, which can specifically identify the five amino acid residues on C terminal. Flag-tag antibodies can be used to detect the expression, intracellular localization, and qualitative or quantitative test of Flag-fused protein.

GST-tag system has the characteristics of high protein expression rate, simple purification process, and convenient GST antibody preparation and so on. GST fusion protein can be dissolved in water and can be extracted from bacterial lysate by affinity chromatography without denaturation. GST-tag can be cleaved and removed by site-specific protease from the fusion protein. As a good immunogen, GST-tag is widely applied to the preparation of immunogen (target protein) for antibodies. Due to the above advantages, the commercialized GST fusion protein expression system and GST-tag antibody system are widely used. In recent years, the application of GST expression-purification system is commonly used in the prokaryotic expression system.

GFP and its mutant EGFP are widely used in the detection of gene expression efficiency and the expression and distribution of target proteins. In general, GFP-tag antiboies can detect not only the GFP or its appropriate mutants, but also the expression, cellular localization and purification of the protein fused with GFP or its mutants. GFP-tag can be on either C terminal or N terminal. This system has been widely used in many kinds of cell types, including bacterium, yeasts, mammalian cells and so on, corresponding GFP-tag antibodies are as well widely used.