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A2220 Sigma

ANTI-FLAG® M2 Affinity Gel

purified immunoglobulin, buffered aqueous glycerol solution

Synonym: ANTI-FLAG® M2 Affinity Agarose Gel, Anti-ddddk, Anti-dykddddk, Monoclonal ANTI-FLAG® M2 antibody produced in mouse



Related Categories Alphabetical Index, Antibodies, Antibodies to Peptide and Protein Fusion Tags, FK-FO, FLAG Affinity Gels,
antibody form   purified immunoglobulin
form   buffered aqueous glycerol solution
application(s)   affinity chromatography: suitable
  immunoprecipitation (IP): suitable
isotype   IgG1
capacity   >0.6 mg/mL, resin binding capacity (FLAG-BAP)
conjugate   agarose conjugate
analyte suitability   proteins (FLAG® Affinity Gels)
shipped in   wet ice
storage temp.   −20°C


Features and Benefits

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General description

Anti-FLAG M2 Affinity gel is a mouse monoclonal antibody that is covalently attached to agarose. The antibody binds FLAG at the N-terminal, Met-N-terminal, C-terminal and internal locations of fusion proteins. Binding is calcium-independent.

Physical form

Suspension in buffered saline containing azide as preservative and 50% glycerol


Anti-FLAG® M2 affinity gel has been used for western blotting, immunoprecipitation and for the purification of FLAG fusion proteins.

Browse additional application references in our FLAG® Literature portal.

Legal Information

ANTI-FLAG is a registered trademark of Sigma-Aldrich Co. LLC

FLAG is a registered trademark of Sigma-Aldrich Co. LLC

Price and Availability

LC-MS Grade Solvents and Reagents

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Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 

Frequently Asked Questions

Is my lysis buffer compatible with Product No. A2220, ANTI-FLAG® M2 Affinity Gel?
The A2220 product information sheet contains a reagent compatibility table located on page 6.  We do not recommend addition of SDS or reducing agents such as DTT, DTE or 2-mercaptoethanol to the resin. If you have a detergent listed in the table in a higher than recommended concentration, we recommend trying to dilute the sample before applying to the resin.  Click here to view the product information sheet: http://www.sigmaaldrich.com/etc/medialib/docs/Sigma/Bulletin/a2220bul.Par.0001.File.tmp/a2220bul.pdf
How should I elute my protein when using Product No. A2220, ANTI-FLAG® M2 Affinity Gel?
Elution with the peptide is the most gentle method.  Acid elution (0.1 M glycine-HCL pH 3.5) is a more stringent method of elution, and should be evaluated for its effect on your protein if it is to be used in downstream applications.  Boiling the resin in sample buffer is the most denaturing condition.  If this condition is used, the resin cannot be re-used, due to the presence of SDS and/or reducing agents. The elution information can be viewed on A2220 Product Information Sheet by clicking on the following link: http://www.sigmaaldrich.com/etc/medialib/docs/Sigma/Bulletin/a2220bul.Par.0001.File.tmp/a2220bul.pdf
When using Product No. A2220, ANTI-FLAG M2 Affinity Gel, I see bands at 20-25 kDa and 50-60 kDa appearing in my Westerns that are not my FLAG-tagged protein. How can I prevent this?
As a result of the conjugation, there may be some M2 antibody that is not conjugated to the resin, but is associated with the resin and may appear in acid elutions as heavy and light chain when using the anti-mouse IgG conjugated secondary antibody.  We recommend a acid wash (0.1 M glycine-HCL pH 3.5) and neutralization of the resin (do not allow the acid wash to sit on the resin longer than 20 minutes) prior to applying the lysate.  Another way to avoid this is to use a directly conjugated FLAG antibody for detection such as product A8592 ant-FLAG M2 HRP, or the rabbit anti-FLAG polyclonal antibody, F7425. To view this information on A2220 Technical Bulletin, click on the following link: http://www.sigmaaldrich.com/etc/medialib/docs/Sigma/Bulletin/a2220bul.Par.0001.File.tmp/a2220bul.pdf
I am using Product No. A2220, ANTI-FLAG M2 Affinity Gel, and have a lot of non-specific proteins that are eluting with my FLAG-tagged protein.  How can I get rid of these?
The product bulletin for Product A2220, anti FLAG M2 affinity gel indicates: Pre-clear lysate with Mouse IgG-Agarose (Product A0919) to remove nonspecific binding proteins. Alternatively, you can use the unconjugated resin (Product 4B200) for this purpose. Other methods to remove non-specific binding from the resin would be to increase the stringency of the washes by increasing salt concentration (the resin can tolerate up to 1M NaCl) or including detergents that are compatible with the resin. http://www.sigmaaldrich.com/etc/medialib/docs/Sigma/Bulletin/a2220bul.Par.0001.File.tmp/a2220bul.pdf
When using ANTI-FLAG M2 Affinity Gel, Product A2220, should I use a 3X FLAG peptide or a 1X FLAG peptide to elute my protein?
If you have a 3X FLAG-tagged protein, then you will need to use the 3X FLAG peptide.  If you have a 1X FLAG-tagged protein, you can use the 1X FLAG peptide or the 3X FLAG peptide.  We have not noticed a significant  difference in elution efficiency by using a 3X FLAG peptide on a 1X FLAG-tagged protein. 
Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis. These documents are located on the product detail page under Useful Links & Tools. Click on the following link to search for a Certificate of Analysis. Please click the following link to see the details on our Product Dating Information.
How do I get lot-specific information or a Certificate of Analysis?
A Certificate of Analysis is available by lot number and can be obtained through our Advanced Search Option: http://www.sigmaaldrich.com/catalog/AdvancedSearchPage.do
How do I find price and availability?
There are several ways to find pricing and availability for our products.  Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers. 
What is the Department of Transportation shipping information for this product?
Transportation information can be found in Section 14 of the product's (M)SDS. To access the shipping information for this material, use the link on the product detail page for the product, or search here. 
My question is not addressed here, how can I contact Technical Service for assistance?
Use the option to the right to "Ask a Question" by email of a Technical Service Scientist.
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Protocols & Articles


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