Antibody-binding proteins: Protein A, Protein G, Protein L

Antibody-binding proteins such as protein A, protein G and protein L are bacterial proteins that bind specifically to antibodies. They are mainly used for antibody purification, immunoprecipitation (IP) and immunodetection. Each antibody binding protein exhibits different affinities to various animal species and antibody subtype. Therefore, it is important to determine the appropriate antibody-binding protein for your sample of interest. TCI has a wide variety of protein A, protein G and protein L conjugates for you to select from.

Protein A

Protein A is a bacterial cell wall component from Staphylococcus aureus that specifically binds to the Fc region of IgG derived from various species including human, rabbit, mouse and cow. Our products consist of a recombinant protein A mutant which allows elution of antibodies under mild conditions (pH 4.0). As there is no change in antibody binding affinity, it can be used in the same way as normal protein A.

Products:

Product Number: P2366 | Product Name: Protein A Recombinant, expressed in Escherichia coli

Product Number: P2407 | Product Name: Protein A Biotin Conjugate

Product Number: P2466 | Product Name: Protein A HRP Conjugate

Product Number: P2461 | Product Name: Protein A Agarose

Application: Purification of human IgG using P2461

Protein A agarose in which protein A is bound to an agarose resin by a covalent coupling method can be used in antibody purification and immunoprecipitation. Antibody purification using protein A agarose usually requires an acidic buffer solution between pH 2.5 and pH 3.0 during elution steps. However, this frequently causes the antibody to undergo acid denaturation, changing its higher-order structure, resulting in antibody aggregation and inactivation. TCI’s protein A agarose uses a genetically modified protein A mutant which allows for the elution of antibodies under mild conditions (pH 4.0), under which most antibodies do not denature.

Protocol:

1. Fill the column with protein A agarose (Product No. P2461) and equilibrate it with binding buffer.
2. Add human IgG.
3. Wash the resin with binding buffer, and then elute antibodies with pH 4.0 and pH 3.0 elution buffer.

Protein G

Protein G is a bacterial cell wall component of Group G Streptococci strain. It binds specifically to the Fc region of immunoglobulins (especially IgG) and weakly to the Fab fragment.

Products:

Product Number: P2808 | Product Name: Protein G Recombinant, expressed in Escherichia coli

Product Number: P2959 | Product Name: Protein G Biotin Conjugate

Product Number: P2962 | Product Name: Protein G HRP Conjugate

Application: Detection of various IgGs by P2962 using the dot-blot method

Protocol:

1. Spot Human IgG, mouse IgG, rabbit IgG, and chicken IgY at a 4-fold dilution from 200 ng onto PVDF membrane.
2. Blocked for 60 minutes at room temperature.
3. Added Protein G HRP Conjugate (Product No. P2962) and incubate for 60 minutes at room temperature.
4. Detect the spots by chemiluminescence.

Protein L

Protein L is a cell wall molecule from the bacterial species Peptostreptococcus magnus. It binds immunoglobulin light chains in a wide range of species including human, mouse, rat, pig, and hamster, and can bind to any immunoglobulin isoform containing a kappa light chain (IgG, IgM, IgA, IgE, and IgD). It can also bind single-chain antibodies (scFv) and Fab fragments with κ light chains.

Products:

Product Number: P3059 | Product Name: Protein L Recombinant, expressed in Escherichia coli

Product Number: P2998 | Product Name: Protein L Biotin Conjugate

Product Number: P2999 | Product Name: Protein L HRP Conjugate

Application: Detection of a κ light chain using P2999

Protocol:

1. Coat mouse IgG κ and IgG λ onto ELISA plates.
2. Block for 2 hours at room temperature.
3. Add Protein L HRP Conjugate (Product No. P2999) and incubate for 30 minutes at room temperature.
4. Add TMB solution and incubate for 30 minutes.
5. Add 1N HCl solution and measure the absorbance at 450 nm.

Related Products

Anti-Protein A Antibodies

Product Number: A3044 | Product Name: Anti-Protein A Chicken Polyclonal Antibody

Product Number: A3045 | Product Name: Anti-Protein A Chicken Polyclonal Antibody Biotin Conjugate

Product Number: A3187 | Product Name: Anti-Protein A Chicken Polyclonal Antibody HRP Conjugate

Peroxidase Substrates

Product Number: T3854 | Product Name: TMB [for ELISA] (Ready-to-use solution)

Product Number: A3176 | Product Name: AzBTS (Ready-to-use solution) [for ELISA]

 Streptavidins

CAS RN: 9013-20-1 | Product Number: S0951 | Product Name: Streptavidin from Streptomyces avidinii

Product Number: S0972 | Product Name: Streptavidin HRP Conjugate

Product Number: S0966 | Product Name: Streptavidin FITC Conjugate

Product Number: S0993 | Product Name: Streptavidin DTBTA-Eu ³+ Conjugate

Product Number: T3531 | Product Name: Streptavidin Maleimide Conjugate

To Learn More:

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