FLAG peptide is a multifunctional fusion tag for the purification of recombinant proteins. FLAG peptide maintances the natural folding of its fusing proteins. FLAG peptide can be removed by enterokinase, and eluted under non-denaturing conditions^[1].

Flag peptide is a highly acidic octapeptide that has a calcium-dependent epitope for monoclonal antibodies, allows elution under non-denaturing conditions, and can be fused to the N-terminus of the target protein. Flag peptide can be captured by the immunoaffinity column in the presence of Ca²⁺ and eluted by EDTA at low concentrations and neutral pH (thus close to physiological conditions)^[1][2].
Reprogramming factors in mammalian cells are purified by FLAG peptide^[3] (1) Transfected cells: HEK293 cells were transfected with FLAG-tagged reprogramming factors, and washed with PBS twice 24 h after transfection. (2) Collect cells: With NP40 cell lysis buffer (50 mM Tris-HCl, pH 7.4, 250 mM NaCl, 5 mM EDTA, 1% NP-40, and protease inhibitors). Centrifuge the cell lysate at 14,500 rpm for 15 min at 4 °C to collect the soluble fraction. (3) Add Anti-Flag Affinity Gel(HY-K0217) to the supernatant and incubate in a cold room with rotation for 16 h. (4) Wash twice with PBS and add 0.1 mg/ml FLAG peptide to elute and retain the FLAG-tagged protein. (5) The eluted protein is dialysed with a dialysis tubing in dialysis buffer (PBS).

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

1012.97

C₄₁H₆₀N₁₀O₂₀

98849-88-8

Solid

White to off-white

Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Lys

DYKDDDDK

Room temperature in continental US; may vary elsewhere.

Sealed storage, away from moisture and light, under nitrogen

*In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light, under nitrogen)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light, under nitrogen). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

* Note: If you choose water as the stock solution, please dilute it to the working solution, then filter and sterilize it with a 0.22 μm filter before use.

• [1]. Einhauer A, et al. The FLAG peptide, a versatile fusion tag for the purification of recombinant proteins. J Biochem Biophys Methods. 2001 Oct 30;49(1-3):455-65.  [Content Brief]

  [2]. Schuster M, et al. Protein expression in yeast; comparison of two expression strategies regarding proteinmaturation. J Biotechnol. 2000 Dec 28;84(3):237-48.  [Content Brief]

  [3]. Min-Joon Han, et al. Purification of functional reprogramming factors in mammalian cell using FLAG –Tag. Biochem Biophys Res Commun. 2017 Oct 14;492(2):154-160.  [Content Brief]