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The FLAG peptide (DYKDDDDK) is one of the most widely used epitope tags in recombinant protein expression, purification, and detection workflows. The short hydrophilic peptide sequence contains a highly charged aspartic acid-rich motif that is efficiently recognized by anti-FLAG monoclonal antibodies, making it useful for affinity purification, immunodetection, protein tracking, and protein interaction studies.
FLAG-tag technology is extensively used in molecular biology, cell biology, protein engineering, and structural biology because the tag is small, minimally disruptive, and compatible with N-terminal, C-terminal, or internal fusion constructs. FLAG-tagged proteins can be detected using anti-DYKDDDDK antibodies in western blotting, ELISA, immunofluorescence, flow cytometry, immunoprecipitation, and affinity chromatography workflows.
Applications of FLAG Peptide
- Competitive elution of FLAG-tagged proteins from anti-FLAG affinity resins
- Affinity purification of recombinant proteins
- Western blot and ELISA assay development
- Immunoprecipitation and pull-down assays
- Protein localization and fluorescence imaging studies
- Protein interaction and structural biology research
- Validation of FLAG-tagged expression constructs
Competitive Elution of FLAG-Tagged Proteins
The FLAG peptide is commonly used for gentle competitive elution of FLAG-tagged fusion proteins from immobilized anti-FLAG antibodies or anti-FLAG agarose affinity matrices. In this workflow, excess soluble FLAG peptide competes with the immobilized FLAG-tagged protein for antibody binding, enabling recovery of purified protein under non-denaturing conditions.
Compared with harsh elution conditions such as low pH or chaotropic reagents, FLAG peptide elution can help preserve protein structure, enzymatic activity, and protein–protein interactions.
Why Use the FLAG Tag System?
- Small 8-amino-acid epitope tag
- Highly specific antibody recognition
- Minimal effect on recombinant protein structure
- Compatible with purification and detection workflows
- Widely validated in molecular biology research
- Suitable for mammalian, bacterial, insect, and yeast expression systems
FLAG Peptide Variants and Related Products
LifeTein offers multiple FLAG-related peptide products for purification, detection, conjugation, and assay development:
3X FLAG Tag System
The 3X FLAG system contains tandem FLAG repeats that enhance antibody binding sensitivity and improve detection of low-abundance proteins. Researchers frequently use 3X FLAG constructs in immunoprecipitation, affinity purification, and weak-expression systems where stronger antibody recognition is beneficial.
FLAG-Cysteine Peptide Applications
FLAG peptides containing an additional cysteine residue enable conjugation to carrier proteins, nanoparticles, fluorophores, or solid supports through thiol-reactive chemistry. These formats are useful for assay development, surface immobilization, and targeted labeling workflows.
Sequence Information
FLAG epitope: DYKDDDDK
Amino acid sequence: Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Lys
The peptide contains multiple negatively charged aspartic acid residues, giving the tag strong hydrophilicity and excellent solvent accessibility when fused to recombinant proteins.
Related Services
Custom peptide synthesis
Fluorescent peptide labeling
Peptide conjugation and carrier protein coupling
ANTI-DYKDDDDK monoclonal antibody
Research Use Only. Not for human or therapeutic use.
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