Mammalian expression systems use various tags to facilitate purification, detection, and visualization of recombinant proteins. Here are some commonly used tags: 

1.His Tag (Histidine Tag): 

     ●      Characteristics: A string of histidine residues (typically 6xHis) allows for easy purification using nickel or cobalt affinity chromatography. It is small and minimally affects protein folding. 

     ●      Applications: Widely used for purifying recombinant proteins in both prokaryotic and eukaryotic systems, including mammalian cells. 

2.FLAG Tag: 

     ●      Characteristics: A short peptide tag (usually DYKDDDDK) that allows for affinity purification using anti-FLAG antibodies. It is small and unlikely to affect protein function. 

     ●      Applications: Commonly used for detection, purification, and immunoprecipitation of proteins. 

3.HA Tag (Hemagglutinin Tag): 

     ●     Characteristics: A small peptide derived from the influenza hemagglutinin protein (YPYDVPDYA), used for affinity purification or detection with anti-HA antibodies. 

     ●     Applications: Often employed in immunoprecipitation, Western blotting, and protein localization studies. 

4.Myc Tag: 

     ●      Characteristics: A small peptide tag (EQKLISEEDL) derived from the c-Myc protein, allowing for detection and purification via anti-Myc antibodies. 

     ●      Applications: Used in Western blotting, immunoprecipitation, and co-immunoprecipitation experiments. 

5.GFP Tag (Green Fluorescent Protein Tag): 

     ●      Characteristics: A fluorescent protein tag that allows for visualization of protein expression and localization in living cells. It can also be used for purification via affinity tags. 

     ●      Applications: Widely used for real-time imaging, localization studies, and FACS sorting. 

6.Fc Tag: 

     ●      Characteristics: The Fc region of an antibody is used as a tag to improve protein stability, facilitate dimerization, and allow for purification via Protein A or G affinity chromatography. 

     ●      Applications: Commonly used for producing therapeutic proteins and enhancing protein solubility. 

Commonly used tags in mammalian expression systems include His, FLAG, HA, Myc, GFP, and Fc tags, each serving different functions such as purification, detection, or visualization. 

GenCefe provide one-stop solutions from codon optimization, gene synthesis, to protein expression and purification. In addition to four conventional expression systems of bacterial, yeast, insect cell, and mammalian cell, we have also developed a patented cell free expression technology, which is suitable for the production of difficult proteins such as toxic proteins and membrane proteins.