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FLAG® Purification

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FLAG® tags enable superior detection and robust purification of recombinant fusion proteins, with proven utility in numerous downstream applications from binding and activity assays to structural analysis. The FLAG® epitope tag is a short, hydrophilic, eight-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. 

Products

western blot (8)

immunoprecipitation (IP) (6)

ELISA (3)

affinity chromatography (3)

immunofluorescence (3)

dot blot (2)

antibodies (18)

primary antibodies (17)

kits (3)

peptides (2)

proteins (2)

resins (1)

unconjugated (8)

agarose (2)

peroxidase (2)

CY3 (1)

FITC (1)

alkaline phosphatase (1)
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ANTI-FLAG<SUP>®</SUP> M2 antibody, Mouse monoclonal
F1804

ANTI-FLAG® M2 antibody, Mouse monoclonal

1 mg/mL, clone M2, affinity isolated antibody, buffered aqueous solution (50% glycerol, 10 mM sodium phosphate, and 150 mM NaCl, pH 7.4)

ANTI-FLAG<SUP>®</SUP> M2 Affinity Gel
A2220

ANTI-FLAG® M2 Affinity Gel

purified immunoglobulin, buffered aqueous glycerol solution

Anti-FLAG<SUP>®</SUP> M2 Magnetic Beads
M8823

Anti-FLAG® M2 Magnetic Beads

affinity isolated antibody

ANTI-FLAG<SUP>®</SUP> M2 antibody, Mouse monoclonal
F3165

ANTI-FLAG® M2 antibody, Mouse monoclonal

clone M2, purified immunoglobulin (Purified IgG1 subclass), buffered aqueous solution (10 mM sodium phosphate, 150 mM NaCl, pH 7.4, containing 0.02% sodium azide)

3X FLAG<SUP>®</SUP> Peptide
F4799

3xFLAG™ Peptide

≥90% (HPLC/MS), lyophilized powder

ANTI-FLAG<SUP>®</SUP> M2-Peroxidase (HRP) antibody, Mouse monoclonal
A8592

ANTI-FLAG® M2-Peroxidase (HRP) antibody, Mouse monoclonal

clone M2, purified immunoglobulin, buffered aqueous glycerol solution

ANTI-FLAG<SUP>®</SUP> antibody produced in rabbit
F7425

ANTI-FLAG® antibody produced in rabbit

affinity isolated antibody, buffered aqueous solution

FLAG<SUP>®</SUP> Peptide
F3290

FLAG® Peptide

≥85% (HPLC), lyophilized powder

EZview<SUP>™</SUP> Red ANTI-FLAG<SUP>®</SUP> M2 Affinity Gel
F2426

EZview™ Red ANTI-FLAG® M2 Affinity Gel

clone M2

ANTI-FLAG<SUP>®</SUP> M2-FITC antibody, Mouse monoclonal
F4049

ANTI-FLAG® M2-FITC antibody, Mouse monoclonal

clone M2, purified immunoglobulin, buffered aqueous solution

ANTI-FLAG<SUP>®</SUP> M2 antibody, Mouse monoclonal
B3111

ANTI-FLAG® M2 antibody, Mouse monoclonal

Clone M2, purified from hybridoma cell culture in bioreactor

ANTI-FLAG<SUP>®</SUP> BioM2 antibody, Mouse monoclonal
F9291

ANTI-FLAG® BioM2 antibody, Mouse monoclonal

clone M2, purified immunoglobulin, buffered aqueous glycerol solution

ANTI-FLAG<SUP>®</SUP> M1 Agarose Affinity Gel
A4596

ANTI-FLAG® M1 Agarose Affinity Gel

FLAG<SUP>®</SUP> Immunoprecipitation Kit
FLAGIPT1

FLAG® Immunoprecipitation Kit

Monoclonal ANTI-FLAG<SUP>®</SUP> antibody produced in rabbit
F2555

Monoclonal ANTI-FLAG® antibody produced in rabbit

clone SIG1-25, ascites fluid

Monoclonal ANTI-FLAG<SUP>®</SUP> M1 antibody
F3040

Monoclonal ANTI-FLAG® M1 antibody

clone M1, purified immunoglobulin, buffered aqueous solution

Monoclonal ANTI-FLAG<SUP>®</SUP> M2-Cy3 antibody, Mouse monoclonal
A9594

Monoclonal ANTI-FLAG® M2-Cy3 antibody, Mouse monoclonal

clone M2, purified immunoglobulin, buffered aqueous solution (Supplied as a solution in 10 mM sodium phosphate)

Monoclonal ANTI-FLAG<SUP>®</SUP> M2-Alkaline Phosphatase antibody produced in mouse
A9469

Monoclonal ANTI-FLAG® M2-Alkaline Phosphatase antibody produced in mouse

clone M2, purified immunoglobulin, buffered aqueous glycerol solution

Amino-terminal FLAG-BAP<SUP>™</SUP> Fusion Protein
P7582

Amino-terminal FLAG-BAP™ Fusion Protein

FLAG<SUP>®</SUP> M Purification Kit
CELLMM2

FLAG® M Purification Kit

For Mammalian expression systems.

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FLAG® Tag Protein Expression

Our FLAG® tag protein expression portfolio includes vectors for efficient expression of recombinant fusion proteins in bacterial and mammalian systems. SnapFast™ vector technology allows you to easily move the gene-of-interest from one vector to another for more efficient and cost-effective cloning.

  • The standard FLAG® peptide (sequence: DYKDDDDK) is a small tag that can be incorporated with minimal risk of steric hindrance or negative impact on protein solubility
  • The 3xFLAG® tag sequence fuses three tandem FLAG® epitopes for enhanced (up to 200X) detection of fusion proteins
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FLAG® Tag Protein Purification

We offer a variety of agarose affinity purification gels, magnetic beads, purification kits, and coated plates for isolation and purification of FLAG® tagged proteins.

  • Agarose affinity gels enable fusion-tagged protein purification using anti-FLAG® antibodies cross-linked to beaded agarose, and are suited for small to large scale purification, these resins are suitable for gravity flow column purification.
  • Anti-FLAG® M2 Magnetic Beads are used to purify recombinant fusion-tagged protein using a magnetic rack or platform to separate beads and isolate protein for rapid processing.
  • Anti-FLAG® High Sensitivity M2-coated 96-well plates are suitable for expression screening, the study of protein-protein interactions, and ELISA assays.
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FLAG® Tag Detection

FLAG® and 3xFLAG™ tags include binding sites for highly specific anti-FLAG® monoclonal antibodies as well as polyclonal antibodies and conjugates for ELISA, blotting applications, immunofluorescence, immunocytochemistry, immunohistochemistry (IHC), blotting, and flow cytometry.

  • The M2 anti-FLAG® antibody binds N-terminal FLAG®, C-terminal FLAG®, and Met-FLAG® fusion proteins.
  • The M1 anti-FLAG® antibody binding is calcium-dependent and specific for the N-terminus of the FLAG® tag.
  • The M5 anti-FLAG® antibody binds N-terminal FLAG® and Met-FLAG® fusion proteins.
 Monoclonal anti-FLAG® M1 antibody produced in mouseMonoclonal anti-FLAG® M2
antibody produced in Mouse		Monoclonal anti-FLAG® M5 antibody produced in Mouse
Catalog NumberF3040F1804F3165F4042
CloneM1M2M2M5
FormBuffered aqueous solutionBuffered aqueous glycerol solution (no sodium azide)Buffered aqueous solution (contains sodium azide)Buffered aqueous solution
Immunogen sequenceDYKDDDDKDYKDDDDKDYKDDDDKDYKDDDDK
Antibody purification methodPurified on Protein A SepharosePurified on proprietary FLAG® peptide-agarosePurified on Protein A SepharosePurified on Protein A Sepharose
KD53.4 nM9.3 nM9.3 nMUnavailable
SpecificityHighly specific. Recognizes only the FLAG® epitope when located at the free N-terminus.Recognizes the FLAG® sequence at N-terminus, Met-N-terminus,
C-terminus or at any internal site of the FLAG® fusion protein.		Strong recognition of the Met-N FLAG® fusion protein. Weak binding with N- or C-terminal fusion protein.
SensitivityDetects 1 ng of FLAG-BAP™ fusion protein on a dot blotDetects 2 ng of protein on a dot blotDetects <1 ng of Met-FLAG® fusion protein on a dot blot
Recommended for:Recommended for the detection of FLAG® fusion proteins in Mammalian, plants and bacterial expression systems. Very useful for affinity purification. Not recommended for detection of cytoplasmic expressed proteins.Western blot detection of target proteins expressed on E. coli,
plants or mammalian
crude cell lysate.		Western blot detection of target proteins expressed on mammalian and drosophilae cell lysate. Particularly useful for the detection of cytoplasmic expressed Met-FLAG fusion proteins. Not recommended for detection of fusion proteins expressed in E. coli
Applications*IP, IC, WB, EIAIP, IC, WB, EIAIP, IC, WB, EIAWB
Special requirementsBinding requires calcium. (Complex will dissociate in the absence of calcium ions)N/AN/AN/A
*IP=immunoprecipitation; IC=immunochemistry, WB=western blot, EIA=enzyme-linked immunosorbent assay (ELISA)

Antibody & binding characteristics

ANTI-FLAG M1

Mouse
IgG2b MAb

ANTI-FLAG M2

Mouse
IgG1 MAb

ANTI-FLAG
M5

Mouse
IgG1 MAb

Unprocessed N-terminal FLAG fusion protein:
Signal peptide - FLAG - Protein		-+Not determined
Met-N-terminal FLAG fusion protein:
Met - FLAG -Protein		-+++
N-terminal FLAG fusion protein:
FLAG - Protein		++Weak
Internal FLAG peptide:
Protein - FLAG - Protein		-+Not determined
C-terminal FLAG fusion protein:
Protein - FLAG		-+Weak
Calcium-dependent binding
(complex is dissociated in EDTA-containing buffer)		+--

Related Resources

  • Brochure: Refine Protein Preparation

    Today, researchers are challenged to create high quality samples for meaningful protein analysis, often using cumbersome traditional sample preparation methods. With over 50 years of experience in developing protein sample preparation technologies, Merck is constantly innovating new tools to offer you rapid and efficient solutions that can be smoothly integrated into your workflow.

  • User Guide: FLAG - Proven System for Detection and Purification of Proteins

    The FLAG Expression System is an established way to express, purify, and detect recombinant fusion proteins. FLAG and 3×FLAG® have proven utility in numerous applications such as Western blotting, immunocytochemistry, immunoprecipitation, flow cytometry, protein purification, and in the study of protein-protein interactions, cell ultrastructure, and protein localization. These small hydrophilic tags facilitate superior detection and purification of recombinant fusion proteins when using our highly specific and sensitive ANTI-FLAG® antibodies.

  • Application Note: EZview™ Red Protein A and ANTI-FLAG® M2 Affinity Gels - Immunoprecipitation with Enhanced Visibility Affinity Beads

    The strength and specificity of interactions between biomolecules have been exploited for years in biochemical research. Affinity-based protein purification techniques have been used extensively to isolate and purify specific proteins or classes of proteins from complex biochemical mixtures, such as cell lysates..

Related Product Categories
Antibody Protein Purification
Antibody purification resins and prepacked columns for lab scale, process scale, and industry scale workflows.
Recombinant/Fusion Tag Protein Purification
Optimize protein purification with our range of affinity resins and buffers for multiple tags and purification techniques.
Protein Electrophoresis Gels & Buffers
Precast polyacrylamide protein gels, running buffers, and hand-casting reagents for hand-pouring polyacrylamide gels for PAGE and SDS-PAGE protein gel electrophoresis.
Protein Electrophoresis Gel Stains
High sensitivity colorimetric and fluorescent protein gel stains, fixing solutions, and de-staining reagents for polyacrylamide gels, agarose gels, and PVDF and nitrocellulose membranes.
Biotinylated Protein Purification
Streptavidin and avidin resins and prepacked columns for small- to large-scale purification of biotinylated proteins and antibodies.
Subcellular Fractionation, Enrichment, and Depletion Reagents
Subcellular fractionation and protein enrichment enable the identification and study of proteins in proteomics research. A wide selection of kits for processing samples from cells, tissues, bacteria, plants, and other sample types is available for subcellular fractionation, protein extraction, depletion, and enrichment.
Cell Lysis Buffers & Protein Extraction Reagents
Protein extraction kits, cell lysis buffers, and reagents for solubilizing proteins from bacteria, yeast, and insect cultures, as well as plant and mammalian cell cultures and tissue samples.
Phosphatase & Protease Inhibitors
Inhibitors and cocktails preserve protein activity during cell lysis and sample prep, preventing proteolysis and dephosphorylation.
Related Applications
Protein Purification
Protein purification techniques, reagents, and protocols for purifying recombinant proteins using methods including, ion-exchange, size-exclusion, and protein affinity chromatography.
Protein Expression
Protein expression technologies for various expression systems supporting research, therapeutics, and vaccine production.
Lysis & Protein Extraction
An overview of cell lysis and protein extraction methods including detergent solubilization, freeze-thaw lysis, osmotic shock, sonication, enzymatic cell lysis, and mechanical disruption techniques such as Dounce, Polytron, and mortar and pestle homogenization.
Protein Pull-Down Techniques
Investigate in vitro protein-protein interactions with pull-down assays, utilizing affinity, GST pull-down, TAP, and co-immunoprecipitation methods.
Protein Concentration & Buffer Exchange
Overview of techniques used to concentrate and clarify protein samples for purification, bioprocessing, and analysis workflows. Includes protocols and videos for filtration and ultrafiltration techniques, protein enrichment, and desalting and buffer exchange using dialysis, diafiltration, and chromatography methods.
Gel Electrophoresis
Protein gel electrophoresis is used to separate proteins for purification, characterization, and detection. Methods such as native PAGE, SDS-PAGE, 2D PAGE, and isoelectric focusing (IEF) are used in preparation for downstream applications including Western blotting, mass spectrometry, and proteomic analysis.
Western Blotting
An overview of the principles and applications of Western blotting for protein detection. Includes links to detailed protocols, videos, and other resources for protein extraction, gel electrophoresis, transfer to PVDF or nitrocellulose membranes, and chemiluminescent, colorimetric, and fluorescent detection methods.
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