Shop All Antibody-Binding Proteins & Conjugates

Pierce™ Recombinant Protein L, Biotinylated (Thermo Scientific™)

Use Thermo Scientific Pierce Biotinylated Recombinant Protein L to probe and detect mouse and human antibodies containing kappa light chains in Western blotting, ELISA, IHC and other immunoassay protocols.

Features of Recombinant Protein L:

• Contains four immunoglobulin-binding domains per protein
• Binds members of all classes of Ig (IgG, IgM, IgA, IgE and IgD) that contain kappa light chains
• Binds single chain variable fragments (scFv) and Fab fragments that contain kappa light chains

Protein L is an immunoglobulin-binding protein that was originally derived from the bacteria Peptostreptococcus magnus, but is now produced recombinantly. Protein L has the unique ability to bind through kappa light chain interactions without interfering with an antibody's antigen-binding site. This gives Protein L the ability to bind a wider range of Ig classes and subclasses than other antibody-binding proteins. Protein L will bind to all classes of Ig (IgG, IgM, IgA, IgE and IgD). Protein L will also bind single chain variable fragments (scFv) and Fab fragments. Protein L binds kappa I, III, and IV in human and kappa I on mouse.

Properties of Recombinant Protein L:
• Source: E. coli
• Molecular Weight: ~35,800 (Apparent MW by SDS-PAGE: 36,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.80
• Isoelectric point (pI): 4.8

Related Products
Pierce™ Recombinant Protein L
Pierce™ Recombinant Protein L, Peroxidase Conjugated

Pierce™ Recombinant Protein L (Thermo Scientific™)

Purified (unconjugated) Thermo Scientific Pierce Recombinant Protein L is useful as the basis for preparing various kinds of probes or affinity media for detection or purification of mouse and human antibodies in immunoassays and antibody purification protocols.

Features of Recombinant Protein L:

• Contains four immunoglobulin-binding domains per protein
• Binds members of all classes of Ig (IgG, IgM, IgA, IgE and IgD) that contain kappa light chains
• Binds single chain variable fragments (scFv) and Fab fragments that contain kappa light chains

Protein L is an immunoglobulin-binding protein that was originally derived from the bacteria Peptostreptococcus magnus, but is now produced recombinantly. Protein L has the unique ability to bind through kappa light chain interactions without interfering with an antibody's antigen-binding site. This gives Protein L the ability to bind a wider range of Ig classes and subclasses than other antibody-binding proteins. Protein L will bind to all classes of Ig (IgG, IgM, IgA, IgE and IgD). Protein L will also bind single chain variable fragments (scFv) and Fab fragments. Protein L binds kappa I, III, and IV in human and kappa I on mouse.

Properties of Recombinant Protein L:
• Source: E. coli
• Molecular Weight: ~35,800 (Apparent MW by SDS-PAGE: 36,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.80
• Isoelectric point (pI): 4.8

Related Products
Pierce™ Recombinant Protein L, Biotinylated
Pierce™ Recombinant Protein L, Peroxidase Conjugated

Pierce™ Recombinant Protein G (Thermo Scientific™)

Purified (unconjugated) Thermo Scientific Pierce Recombinant Protein G is useful as the basis for preparing various kinds of probes or affinity media for detection or purification of rabbit and human antibodies, especially IgG isotypes, in immunoassays and antibody purification protocols.

Features of Recombinant Protein G:

• Contains two Fc-binding domains per protein
• Better than Protein A for mouse (incl. IgG1), human (incl. IgG3) and rat, goat and cow antibodies
• Poorer than Protein A for guinea pig, pig, dog and cat
• Does not bind human IgM, IgD or IgA

Protein G is a bacterial cell wall protein isolated from group G Streptococci. DNA sequencing of native Protein G identifies two IgG-binding domains and sites for albumin and cell surface binding. The albumin and cell surface binding domains have been eliminated from Recombinant Protein G to reduce nonspecific binding and, therefore, can be used to separate IgG from crude samples. Optimal binding occurs at pH 5, although binding is also effective at pH 7.0 to 7.2.

Properties of Recombinant Protein G:
• Source: E. coli
• Molecular Weight: ~21,600 (Apparent MW by SDS-PAGE: 32,000)
• Form: salt-free powder
• A280 of 0.1% solution: 1.0
• Isoelectric point (pI): 4.5

Because Protein G has greater affinity than Protein A for most mammalian IgGs, it may be used for the purification of mammalian IgGs that do not bind well to Protein A. Protein G binds with significantly greater capacity than Protein A to several IgG subclasses such as human IgG3, mouse IgG1 and rat IgG2a. However, Protein G does not bind to human IgM, IgD and IgA. Differences in binding characteristics between Protein A and Protein G may be explained by the differing compositions in the IgG-binding sites of each protein. The tertiary structures of these proteins are very similar although their amino acid compositions are significantly different.

There are inconsistencies in reported binding properties of IgG to Protein G. Variations in isolation and manufacturing methods for Protein G may affect IgG binding, partially because there are differing numbers of IgG-binding sites on various sources of Protein G. Binding studies have been performed using native Protein G and several different recombinant forms. Several assay methods have been used to determine relative affinity, including radiolabeling experiments and ELISA techniques. The differing affinity assays may explain some of the inconsistencies. In addition, there are significant binding differences when different buffers are used. Approximately 44% more IgG from rat serum bound to Protein G when Protein G Binding Buffer was used as compared with 20 mM Tris Buffer, pH 7.5.

Related Products
Pierce™ Recombinant Protein G, Biotinylated
Pierce™ Recombinant Protein G, Peroxidase Conjugated

Pierce™ Recombinant Protein G, Peroxidase Conjugated (Thermo Scientific™)

Purified (unconjugated) Thermo Scientific Pierce Recombinant Protein G is useful as the basis for preparing various kinds of probes or affinity media for detection or purification of rabbit and human antibodies, especially IgG isotypes, in immunoassays and antibody purification protocols.

Features of Recombinant Protein G:

• Contains two Fc-binding domains per protein
• Better than Protein A for mouse (incl. IgG1), human (incl. IgG3) and rat, goat and cow antibodies
• Poorer than Protein A for guinea pig, pig, dog and cat
• Does not bind human IgM, IgD or IgA

Protein G is a bacterial cell wall protein isolated from group G Streptococci. DNA sequencing of native Protein G identifies two IgG-binding domains and sites for albumin and cell surface binding. The albumin and cell surface binding domains have been eliminated from Recombinant Protein G to reduce nonspecific binding and, therefore, can be used to separate IgG from crude samples. Optimal binding occurs at pH 5, although binding is also effective at pH 7.0 to 7.2.

Properties of Recombinant Protein G:
• Source: E. coli
• Molecular Weight: ~21,600 (Apparent MW by SDS-PAGE: 32,000)
• Form: salt-free powder
• A280 of 0.1% solution: 1.0
• Isoelectric point (pI): 4.5

Because Protein G has greater affinity than Protein A for most mammalian IgGs, it may be used for the purification of mammalian IgGs that do not bind well to Protein A. Protein G binds with significantly greater capacity than Protein A to several IgG subclasses such as human IgG3, mouse IgG1 and rat IgG2a. However, Protein G does not bind to human IgM, IgD and IgA. Differences in binding characteristics between Protein A and Protein G may be explained by the differing compositions in the IgG-binding sites of each protein. The tertiary structures of these proteins are very similar although their amino acid compositions are significantly different.

There are inconsistencies in reported binding properties of IgG to Protein G. Variations in isolation and manufacturing methods for Protein G may affect IgG binding, partially because there are differing numbers of IgG-binding sites on various sources of Protein G. Binding studies have been performed using native Protein G and several different recombinant forms. Several assay methods have been used to determine relative affinity, including radiolabeling experiments and ELISA techniques. The differing affinity assays may explain some of the inconsistencies. In addition, there are significant binding differences when different buffers are used. Approximately 44% more IgG from rat serum bound to Protein G when Protein G Binding Buffer was used as compared with 20 mM Tris Buffer, pH 7.5.

Related Products
Pierce™ Recombinant Protein G
Pierce™ Recombinant Protein G, Biotinylated

Pierce™ Recombinant Protein L, Peroxidase Conjugated (Thermo Scientific™)

Use Thermo Scientific Pierce Recombinant Peroxidase Conjugated Protein L to probe and detect mouse and human antibodies containing kappa light chains in Western blotting, ELISA, IHC and other immunoassay protocols.

Features of Recombinant Protein L:

• Contains four immunoglobulin-binding domains per protein
• Binds members of all classes of Ig (IgG, IgM, IgA, IgE and IgD) that contain kappa light chains
• Binds single chain variable fragments (scFv) and Fab fragments that contain kappa light chains

Protein L is an immunoglobulin-binding protein that was originally derived from the bacteria Peptostreptococcus magnus, but is now produced recombinantly. Protein L has the unique ability to bind through kappa light chain interactions without interfering with an antibody's antigen-binding site. This gives Protein L the ability to bind a wider range of Ig classes and subclasses than other antibody-binding proteins. Protein L will bind to all classes of Ig (IgG, IgM, IgA, IgE and IgD). Protein L will also bind single chain variable fragments (scFv) and Fab fragments. Protein L binds kappa I, III, and IV in human and kappa I on mouse.

Properties of Recombinant Protein L:
• Source: E. coli
• Molecular Weight: ~35,800 (Apparent MW by SDS-PAGE: 36,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.80
• Isoelectric point (pI): 4.8

Related Products
Pierce™ Recombinant Protein L
Pierce™ Recombinant Protein L, Biotinylated

Pierce™ Recombinant Protein A/G, Alkaline Phosphatase Conjugated (Thermo Scientific™)

Use Thermo Scientific Pierce Recombinant Alkaline Phosphatase Conjugated Protein A/G to probe and detect antibodies, especially IgG isotypes, of many different species hosts in Western blotting, ELISA, IHC and other immunoassay protocols.

Features of Recombinant Protein A/G:

• Contains four Fc-binding domains from Protein A and two from Protein G
• Provides binding for all antibody species and subclasses recognized by either Protein A or Protein G

The extended Fc-binding properties of Protein A/G make it a popular tool in the investigation and purification of immunoglobulins. Protein A/G binds to all human IgG subclasses, IgA, IgE, IgM and to a lesser extent IgD; however, it does not bind mouse IgA, IgM or murine serum albumin. Protein A/G is an excellent tool for purification and detection of mouse monclonal antibodies from IgG subclasses without interference from these other serum proteins. Individual subclasses of mouse monoclonals are most likely to have stronger affinity to this chimeric protein than to either Protein A or Protein G.

Properties of Recombinant Protein A/G:
• Source: E. coli
• Molecular weight: 50,460 (Apparent MW by SDS-PAGE: 40,000-45,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.505
• Isoelectric point (pI): 4.65

Gene fusion of the Fc-binding domains of Protein A and Protein G has resulted in production of a structurally and functionally chimeric protein with broader binding than either Protein A or Protein G alone. During fusion, the Protein G gene sequence coding for the serum albumin-binding site is eliminated. This protein is expressed in E. coli and secreted into the surrounding medium during fermentation. The product obtained is consistent in quality and yield because the bacterial host is engineered to be deficient in major proteolytic activities. Binding is less pH-dependent than either Protein A or Protein G alone, occurring well at pH 5 to 8.

Related Products
Pierce™ Recombinant Protein A/G
Pierce™ Recombinant Protein A/G, Peroxidase Conjugated

Pierce™ Recombinant Protein A (Thermo Scientific™)

Purified (unconjugated) Thermo Scientific Pierce Recombinant Protein A is useful as the basis for preparing various kinds of probes or affinity media for detection or purification of rabbit and human antibodies, especially IgG isotypes, in immunoassays and antibody purification protocols.

Features of Recombinant Protein A:

• Contains four Fc-binding domains per protein
• Better than Protein G for polyclonal IgG from rabbit, pig, dog and cat serum
• Poorer than Protein G for mouse IgG1, human IgG3 and rat, goat and cow antibodies

Protein A is a cell wall component produced by several strains of Staphylococcus aureus that consists of a single polypeptide chain and contains little or no carbohydrate. Recombinant Protein A is produced in E. coli and functions essentially the same as native Protein A. The Protein A molecule contains four high-affinity binding sites capable of interacting with the Fc region from IgG of several species including human and rabbit. Optimal binding occurs at pH 8.2, although binding is also effective at neutral or physiological conditions (pH 7.0 to 7.6).

The interaction between Protein A and IgG is not equivalent for all species. Even within a species, Protein A interacts with some subclasses of IgG and not others. For instance, human IgG1, IgG2 and IgG4 bind strongly, while IgG3 does not bind. There are also many instances in which monoclonal antibodies do not bind to Protein A, especially the majority of rat immunoglobulins and mouse IgG1.

Properties of Recombinant Protein A:
• Source: E. coli
• Molecular Weight: ~44,600 (Apparent MW by SDS-PAGE: 45,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.165
• Isoelectric point (pI): 4.7-4.8

Related Products
Pierce™ Recombinant Protein A, Peroxidase Conjugated

Pierce™ Protein A (Thermo Scientific™)

Use this purified form of Thermo Scientific Pierce Protein A to probe and detect rabbit and human antibodies, especially IgG isotypes, in western blotting, ELISA, IHC and other immunoassay protocols.

Features of Protein A:

• Contains four Fc-binding domains per protein
• Better than Protein G for polyclonal IgG from rabbit, pig, dog and cat serum
• Poorer than Protein G for mouse IgG1, human IgG3 and rat, goat and cow antibodies

Protein A is a cell wall component produced by several strains of Staphylococcus aureus that consists of a single polypeptide chain and contains little or no carbohydrate. The Protein A molecule contains four high-affinity binding sites capable of interacting with the Fc region from IgG of several species including human and rabbit. Optimal binding occurs at pH 8.2, although binding is also effective at neutral or physiological conditions (pH 7.0 to 7.6).

Properties of Native Protein A:
• Source: Staphylococcus aureus
• Molecular weight: 46,762 (Apparent MW by SDS-PAGE: 42,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.137 (theoretical)
• Isoelectric point (pI): 5.16 (theoretical)

The interaction between Protein A and IgG is not equivalent for all species. Even within a species, Protein A interacts with some subclasses of IgG and not others. For instance, human IgG1, IgG2 and IgG4 bind strongly, while IgG3 does not bind. There are also many instances in which monoclonal antibodies do not bind to Protein A, especially the majority of rat immunoglobulins and mouse IgG1.

Related Products
Pierce™ Protein A, Biotinylated

Pierce™ Recombinant Protein A/G, Peroxidase Conjugated (Thermo Scientific™)

Use Thermo Scientific Pierce Recombinant Peroxidase Conjugated Protein A/G to probe and detect antibodies, especially IgG isotypes, of many different species hosts in Western blotting, ELISA, IHC and other immunoassay protocols.

Features Recombinant Protein A/G:

• Contains four Fc-binding domains from Protein A and two from Protein G
• Provides binding for all antibody species and subclasses recognized by either Protein A or Protein G

The extended Fc-binding properties of Protein A/G make it a popular tool in the investigation and purification of immunoglobulins. Protein A/G binds to all human IgG subclasses, IgA, IgE, IgM and to a lesser extent IgD; however, it does not bind mouse IgA, IgM or murine serum albumin. Protein A/G is an excellent tool for purification and detection of mouse monclonal antibodies from IgG subclasses without interference from these other serum proteins. Individual subclasses of mouse monoclonals are most likely to have stronger affinity to this chimeric protein than to either Protein A or Protein G.

Properties of Recombinant Protein A/G:
• Source: E. coli
• Molecular weight: 50,460 (Apparent MW by SDS-PAGE: 40,000-45,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.505
• Isoelectric point (pI): 4.65

Gene fusion of the Fc-binding domains of Protein A and Protein G has resulted in production of a structurally and functionally chimeric protein with broader binding than either Protein A or Protein G alone. During fusion, the Protein G gene sequence coding for the serum albumin-binding site is eliminated. This protein is expressed in E. coli and secreted into the surrounding medium during fermentation. The product obtained is consistent in quality and yield because the bacterial host is engineered to be deficient in major proteolytic activities. Binding is less pH-dependent than either Protein A or Protein G alone, occurring well at pH 5 to 8.

Related Products
Pierce™ Recombinant Protein A/G
Pierce™ Recombinant Protein A/G, Alkaline Phosphatase Conjugated

Pierce™ Recombinant Protein A, Peroxidase Conjugated (Thermo Scientific™)

Use Thermo Scientific Pierce Recombinant Peroxidase Conjugated Protein A to probe and detect rabbit and human antibodies, especially IgG isotypes, in Western blotting, ELISA, IHC and other immunoassay protocols.

Features of Recombinant Peroxidase Conjugated Protein A:

• Contains four Fc-binding domains per protein
• Better than Protein G for polyclonal IgG from rabbit, pig, dog and cat serum
• Poorer than Protein G for mouse IgG1, human IgG3 and rat, goat and cow antibodies

Protein A is a cell wall component produced by several strains of Staphylococcus aureus that consists of a single polypeptide chain and contains little or no carbohydrate. Recombinant Protein A is produced in E. coli and functions essentially the same as native Protein A. The Protein A molecule contains four high-affinity binding sites capable of interacting with the Fc region from IgG of several species including human and rabbit. Optimal binding occurs at pH 8.2, although binding is also effective at neutral or physiological conditions (pH 7.0 to 7.6).

Properties of Recombinant Protein A:
• Source: E. coli
• Molecular Weight: ~44,600 (Apparent MW by SDS-PAGE: 45,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.165
• Isoelectric point (pI): 4.7-4.8

The interaction between Protein A and IgG is not equivalent for all species. Even within a species, Protein A interacts with some subclasses of IgG and not others. For instance, human IgG1, IgG2 and IgG4 bind strongly, while IgG3 does not bind. There are also many instances in which monoclonal antibodies do not bind to Protein A, especially the majority of rat immunoglobulins and mouse IgG1.

Related Products
Pierce™ Recombinant Protein A

Pierce™ Recombinant Protein A/G (Thermo Scientific™)

Purified (unconjugated) Thermo Scientific Pierce Recombinant Protein A/G is useful as the basis for preparing various kinds of probes or affinity media for detection or purification of rabbit and human antibodies, especially IgG isotypes, in immunoassays and antibody purification protocols.

Features of Recombinant Protein A/G:

• Contains four Fc-binding domains from Protein A and two from Protein G
• Provides binding for all antibody species and subclasses recognized by either Protein A or Protein G

The extended Fc-binding properties of Protein A/G make it a popular tool in the investigation and purification of immunoglobulins. Protein A/G binds to all human IgG subclasses, IgA, IgE, IgM and to a lesser extent IgD; however, it does not bind mouse IgA, IgM or murine serum albumin. Protein A/G is an excellent tool for purification and detection of mouse monclonal antibodies from IgG subclasses without interference from these other serum proteins. Individual subclasses of mouse monoclonals are most likely to have stronger affinity to this chimeric protein than to either Protein A or Protein G.

Properties of Recombinant Protein A/G:
• Source: E. coli
• Molecular weight: 50,460 (Apparent MW by SDS-PAGE: 40,000-45,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.505
• Isoelectric point (pI): 4.65

Gene fusion of the Fc-binding domains of Protein A and Protein G has resulted in production of a structurally and functionally chimeric protein with broader binding than either Protein A or Protein G alone. During fusion, the Protein G gene sequence coding for the serum albumin-binding site is eliminated. This protein is expressed in E. coli and secreted into the surrounding medium during fermentation. The product obtained is consistent in quality and yield because the bacterial host is engineered to be deficient in major proteolytic activities. Binding is less pH-dependent than either Protein A or Protein G alone, occurring well at pH 5 to 8.

Related Products
Pierce™ Recombinant Protein A/G, Alkaline Phosphatase Conjugated
Pierce™ Recombinant Protein A/G, Peroxidase Conjugated

Pierce™ Protein A, Biotinylated (Thermo Scientific™)

Use this biotinylated form of Thermo Scientific Pierce Protein A to probe and detect rabbit and human antibodies, especially IgG isotypes, in Western blotting, ELISA, IHC and other immunoassay protocols.

Features of Protein A:

• Contains four Fc-binding domains per protein
• Better than Protein G for polyclonal IgG from rabbit, pig, dog and cat serum
• Poorer than Protein G for mouse IgG1, human IgG3 and rat, goat and cow antibodies

Protein A is a cell wall component produced by several strains of Staphylococcus aureus that consists of a single polypeptide chain and contains little or no carbohydrate. The Protein A molecule contains four high-affinity binding sites capable of interacting with the Fc region from IgG of several species including human and rabbit. Optimal binding occurs at pH 8.2, although binding is also effective at neutral or physiological conditions (pH 7.0 to 7.6).

Properties of Native Protein A:
• Source: Staphylococcus aureus
• Molecular weight: 46,762 (Apparent MW by SDS-PAGE: 42,000)
• Form: salt-free powder
• A280 of 0.1% solution: ~0.137 (theoretical)
• Isoelectric point (pI): 5.16 (theoretical)

The interaction between Protein A and IgG is not equivalent for all species. Even within a species, Protein A interacts with some subclasses of IgG and not others. For instance, human IgG1, IgG2 and IgG4 bind strongly, while IgG3 does not bind. There are also many instances in which monoclonal antibodies do not bind to Protein A, especially the majority of rat immunoglobulins and mouse IgG1.

Related Products
Pierce™ Protein A

Pierce™ Recombinant Protein G, Biotinylated (Thermo Scientific™)

Use Thermo Scientific Pierce Biotinylated Recombinant Protein G to probe and detect mouse and human antibodies, especially IgG isotypes, in Western blotting, ELISA, IHC and other immunoassay protocols.

Features of Biotinylated Recombinant Protein G:

• Contains two Fc-binding domains per protein
• Better than Protein A for mouse (incl. IgG1), human (incl. IgG3) and rat, goat and cow antibodies
• Poorer than Protein A for guinea pig, pig, dog and cat
• Does not bind human IgM, IgD or IgA

Protein G is a bacterial cell wall protein isolated from group G Streptococci. DNA sequencing of native Protein G identifies two IgG-binding domains and sites for albumin and cell surface binding. The albumin and cell surface binding domains have been eliminated from Recombinant Protein G to reduce nonspecific binding and, therefore, can be used to separate IgG from crude samples. Optimal binding occurs at pH 5, although binding is also effective at pH 7.0 to 7.2.

Properties of Recombinant Protein G:
• Source: E. coli
• Molecular Weight: ~21,600 (Apparent MW by SDS-PAGE: 32,000)
• Form: salt-free powder
• A280 of 0.1% solution: 1.0
• Isoelectric point (pI): 4.5

Because Protein G has greater affinity than Protein A for most mammalian IgGs, it may be used for the purification of mammalian IgGs that do not bind well to Protein A. Protein G binds with significantly greater capacity than Protein A to several IgG subclasses such as human IgG3, mouse IgG1 and rat IgG2a. However, Protein G does not bind to human IgM, IgD and IgA. Differences in binding characteristics between Protein A and Protein G may be explained by the differing compositions in the IgG-binding sites of each protein. The tertiary structures of these proteins are very similar although their amino acid compositions are significantly different.

There are inconsistencies in reported binding properties of IgG to Protein G. Variations in isolation and manufacturing methods for Protein G may affect IgG binding, partially because there are differing numbers of IgG-binding sites on various sources of Protein G. Binding studies have been performed using native Protein G and several different recombinant forms. Several assay methods have been used to determine relative affinity, including radiolabeling experiments and ELISA techniques. The differing affinity assays may explain some of the inconsistencies. In addition, there are significant binding differences when different buffers are used. Approximately 44% more IgG from rat serum bound to Protein G when Protein G Binding Buffer was used as compared with 20 mM Tris Buffer, pH 7.5.

Related Products
Pierce™ Recombinant Protein G
Pierce™ Recombinant Protein G, Peroxidase Conjugated