FLAG peptide is an eight amino acids peptide (Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Lys) with an enterokinase-cleavage site; designed for antibody-mediated identification and purification of recombinant proteins.

Fusion protein technology has become an important tool for solving numerous problems linked to recombinant protein production. The properties of the additional tag facilitate identification and provide a one-step purification procedure of the fusion protein by passing cell extracts or supernatants through columns of an appropriate matrix. FLAG peptide allows elution under non-denaturing conditions. Several antibodies against FLAG peptide have been developed. One antibody, M1, binds the peptide in the presence of bivalent metal cations, preferably Ca²⁺. Elution is effected by chelating agents. Another strategy is competitive elution with excess of free FLAGe peptide. Antibodies M2 and M5 are applied in this procedure^[1]. The Flag-tag is first described as a calcium-dependent epitope of a monoclonal antibody. It is a highly acidic octapeptide which can be N-terminally fused to the protein of interest. As a very hydrophilic peptide the Flag–tag has a high surface probability. Flag-fusion proteins can be captured by an immunoaffinity column in the presence of Ca²⁺ and eluted byEDTA at low concentrations, neutral pH and thus, nearly physiological conditions^[2].

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

1012.97

C₄₁H₆₀N₁₀O₂₀

98849-88-8

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

DYKDDDDK

Room temperature in continental US; may vary elsewhere.

Protect from light, stored under nitrogen

Powder	-80deg;C	2 years
	-20deg;C	1 year

*In solvent : -80deg;C, 6 months; -20deg;C, 1 month (protect from light, stored under nitrogen)

In Vitro:;

H₂O : 100 mg/mL (98.72 mM; Need ultrasonic)

*

请根据产品在不同溶剂中的溶解度选择合适的溶剂配制储备液；一旦配成溶液，请分装保存，避免反复冻融造成的产品失效。
储备液的保存方式和期限：-80°C, 6 months; -20°C, 1 month (protect from light, stored under nitrogen)。-80°C 储存时，请在 6 个月内使用，-20°C 储存时，请在 1 个月内使用。

• [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.

  [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.