Selection Guide: Peptide Tags
Do you know which tag is best for your protein? Explore the options below to choose the best tag for your protein and application.
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Features
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When to Use |
When Not to Use |
- Distinct types of his tags are available, including the 6xHN tag (12 amino acids)
- Most common affinity tag used to purify proteins
- Binds to coordinated metals such as Ni2+ or Co2+
- His-tagged proteins can be eluted with imidazole or low pH buffer
- A his tag can be incorporated on either the N- or C-terminus
- Can be expressed in bacterial, yeast, mammalian, and baculovirus-infected insect cells or in vitro
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- When a small tag is required to minimize its effect on protein function
- When a low metabolic load is needed to maintain normal cell physiology and/or to increase protein expression
- When a high capacity affinity resin is needed to increase yields and reduce costs
- To reduce the cost of affinity purification by using an inexpensive resin
- To reduce the cost of affinity purification by using a resin that can be regenerated multiple times
- When the choice to purify a protein under native or denaturing conditions is needed
- When mild elution conditions are necessary
- For large-scale and HTP purifications
- To study protein-protein or nucleic acid-protein interactions involving an immobilized his-tagged protein
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- When the tagged protein sample is in the presence of other metals or chelating reagents (EDTA)
- When eluting proteins with imidazole buffers will interfere with downstream processes such as crystallography or NMR applications (elution with low pH buffers or desalting may overcome this issue)
- When high concentrations of reducing agents (DTT) are necessary
- When trying to purify metalloproteins
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Features
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When to Use |
When Not to Use |
- Small peptide tag (8 amino acids)
- Binds to the Anti-DYKDDDDK Antibody
- FLAG-tagged proteins can be eluted with low pH buffer or sample buffer
- A FLAG-tag can be incorporated on either the N- or C-terminus
- Can be expressed in bacterial, yeast, mammalian, and baculovirus-infected insect cells
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- When a small tag is required to minimize its effect on protein function
- When a low metabolic load is needed to maintain normal cell physiology and/or to increase protein expression
- When a hydrophillic tag is required
- When highly specific detection is necessary
- When purification of highly pure protein at very low yields is acceptable
- To monitor recombinant protein expression in bacterial, yeast, mammalian, or insect cells
- For co-immunoprecipitation studies, Western blots, and flow cytometry
- To monitor subcellular localization of the tagged protein in mammalian cells
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- When an inexpensive purification resin is needed
- When low pH elution conditions can damage the target protein or affect its functionality (This issue can be overcome by competitive elution with FLAG peptide)
- For applications requiring a resin with a high binding capacity or high yields
- When matrix stability/shelf life is a factor
- For large-scale and HTP purifications
- When regeneration of the matrix is desired
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Features
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When to Use |
When Not to Use |
- Small peptide tag (11 amino acids)
- Binds to the c-Myc Monoclonal Antibody
- Myc-tagged protein can be eluted with low pH buffer or sample buffer
- A Myc-tag can be incorporated on either the N-terminus, the C-terminus, or internally
- Can be expressed in bacterial, yeast, mammalian, and baculovirus-infected insect cells
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- When a small tag is required to minimize its effect on protein function
- When a low metabolic load is needed to maintain normal cell physiology and/or to increase protein expression
- To monitor recombinant protein expression in bacterial, yeast, mammalian, or insect cells
- For co-immunoprecipitation studies, Western blots, and flow cytometry
- To monitor subcellular localization of the tagged protein in mammalian cells
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- When an inexpensive purification resin is needed
- When low pH elution conditions can damage the target protein or affect its functionality
- For applications requiring a resin with a high binding capacity or high yields
- When matrix stability/shelf-life is a factor
- For large-scale and HTP purifications
- When regeneration of the matrix is desired
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Features
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When to Use |
When Not to Use |
- Small peptide tag (9 amino acids)
- Binds to the HA Tag Polyclonal Antibody
- An HA-tag can be incorporated on either the N-terminus, the C-terminus, or internally
- Can be expressed in bacterial, yeast, mammalian, and baculovirus-infected insect cells
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- When a small tag is required to minimize its effect on protein function
- When a low metabolic load is needed to maintain normal cell physiology and/or to increase protein expression
- To monitor recombinant protein expression in bacterial, yeast, mammalian, or insect cells
- For co-immunoprecipitation studies and Western blots
- To monitor subcellular localization of the tagged protein in mammalian cells
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- As an affinity tag to purify tagged protein
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Features
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When to Use |
When Not to Use |
- Large protein tag (glutathione S-transferase, 26 kDa protein)
- Binds to glutathione
- GST-tagged proteins can be eluted with reduced glutathione
- A GST-tag can be incorporated on either the N- or C-terminus
- Can be expressed in bacterial, yeast, mammalian, and baculovirus-infected insect cells
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- To reduce the cost of affinity purification by using an inexpensive resin
- To reduce the cost of affinity purification by using a resin that can be regenerated multiple times
- When mild elution conditions are necessary
- To protect some recombinant proteins from intracellular protease cleavage
- When it is necessary to use a tag that may enhance the solubility of the tagged protein
- When removal of the tag is necessary
- To study protein-protein or protein-nucleic acid interactions
- To use as an antigen for immunology or vaccination studies
- When the protein needs to be purified under strong reducing conditions
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- When a low metabolic load is needed to maintain normal cell physiology and/or to increase protein expression
- When a small tag is required
- When a homodimeric protein tag is not suitable
- When trying to isolate an oligomeric protein
- When purification under denaturing conditions is required
- When the target protein contains disulfides which may be reduced by the elution buffer
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