Epitope tag for recombinant protein purification & detection


With proven utility in numerous applications, FLAG® tags provide superior detection and purification of recombinant fusion proteins. The FLAG® epitope tag is a short, hydrophilic, 8-amino acid peptide (DYKDDDDK tag), that is readily cleavable by enterokinase (Ek). Due to its small size and hydrophilic nature, the FLAG® tag commonly resides on the surface of the fusion protein, minimizing effects on function, secretion, or transport of the fusion protein. Regardless of your final application, we have the tools needed to express, purify, and detect FLAG® fusion proteins.

Learn more about how the FLAG® tag works


Recombinant protein production has been improved by advances in fusion protein technology. While the original FLAG® peptide is sensitive, the 3xFLAG® tag provides enhanced detection up to 200 times more than any other protein marker. Our portfolio includes vectors for both bacterial and mammalian systems, using T7, Tac or CMV promoters in our premier SnapFast™ system.

FLAG® and 3xFLAG® peptides
FLAG® Vectors





Protein purification with FLAG® and 3xFLAG® sequences provide single band purity with one chromatography step. Depending on your desired method and the terminus of the FLAG® tag peptide (N, met-N, or C), we have affinity gels, 96 well-plate formats, and purification kits for FLAG® tag purification.

FLAG® and 3xFLAG® peptides
FLAG® Affinity Gels
FLAG® Purification Kits
FLAG® Control Proteins   




FLAG® and 3xFLAG® tags include binding sites for highly specific anti-FLAG® monoclonal antibodies, as well as polyclonal antibodies and conjugates. Fusion proteins containing the FLAG® tag are commonly used in immunodetection-based downstream applications, such as Western blotting, immunocytochemistry, EIA, dot blotting, ELISA, and immunohistochemistry.

FLAG® Antibodies
FLAG® Secondary Antibodies
FLAG® Antibody Conjugates
FLAG® Control Proteins

Need help selecting the correct anti FLAG® antibody for your application? Visit our anti-FLAG® antibody selection page to learn more about the M1, M2, and M5 monoclonal antiFLAG® antibodies.