Cusabio C-terminal HA-tagged Recombinant

What is an HA tag?

An HA tag is derived from the human influenza C-terminal hemagglutinin (HA)-tagged recombinant molecule corresponding to amino acids 98-106. It has been widely used as a general epitope tag in expression vectors. The HA tag does not appear to interfere with the bioactivity or biodistribution of the recombinant HA-tagged protein.

What are the nucleotide and amino acid sequences of the peptide tag HA?

The nucleotide sequence of the HA tag is 5′ TAC CCA TAC GAT GTT CCA GAT TAC GCT 3′ or 5′ TAT CCA TAT GAT GTT CCA GAT TAT GCT 3′. The amino acid sequence of the HA tag is: YPYDVPDYA

Why use an HA tag for protein expression and production?

Adding an HA tag to the C or N terminus of a protein can facilitate its detection, isolation, and purification by HA tag-specific antibodies. Sino Biological has developed HA tag-specific antibodies for ELISA, Western Blotting, immunofluorescence, and immunoprecipitation for the detection of HA-tagged protein. It can also be conjugated to agarose beads for affinity purification of HA-tagged proteins.


Recombinant protein for human HA tag

Source: Baculovirus (Sf9 insect cells)

Fountain: Sf9 (baculovirus)

Protein/peptide type: recombinant protein

Purity: >90%, per SDS-PAGE

Note on endotoxins: <0.1ng/ug


  • Dilutions: SDS Page
  • Theoretical MW: 72 kDa.
  • Disclaimer Note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post-translational modifications, post-translational cleavages, relative charges, and other experimental factors.

Packaging, storage and formulations

  • Storage: Store at 4C. Do not freeze.
  • Buffer: 10 mM sodium phosphate (pH 7.2), 150 mM NaCl
  • Concentration: 1.7mg/mL
  • Purity: >90%, per SDS-PAGE

Alternative names for the recombinant human HA marker protein

  • HA epitope tag
  • HA label
  • SAY OH
  • hemagglutinin


Human influenza hemagglutinin (HA) is a glycoprotein required for human virus infectivity and is expressed as a homotrimer on the surface of the viral capsid. As the main antigen of the influenza virus, HA is constantly evolving to escape herd immunity through an antigenic shift that can lead to pandemics. The HA tag (YPYDVPDYA tag) has a molecular weight of 1.1 kDa and is a linear epitope derived from amino acids 98-106 of the HA protein.

It is widely used as a general epitope tag in expression vectors. The HA tag is often added to the N- or C-terminus of a protein of interest to facilitate protein purification, detection, and labelling by anti-HA antibodies (3, 4). The HA tag is cleaved by caspase 3/7, resulting in a complete loss of immunoreactivity, making it unsuitable for the study of apoptosis.

How are HA-tagged proteins purified?

The HA-tagged recombinant protein can be affinity purified directly from cell culture lysate or supernatant. The HA-tagged protein is bound to conjugated HA-tag-specific monoclonal antibody on an agarose gel. After washing away residual impurities, bound HA-tagged proteins can be eluted from the affinity column by a high concentration of HA-tagged peptide or by a low pH buffer.

How do I remove the HA tag after purification?

In some applications, it is desirable to remove the HA tag, for example for protein crystallization. To allow cleavage of the HA tag, it is necessary to design a protease cleavage site between the tag and the protein. An EK cleavage site behind the HA tag (HA-EK site protein structure) may allow complete removal of the HA tag and cleavage site, leaving no additional amino acids after specific cleavage of the HA tag. For more information on cleavage site and tag removal by EK and HRV-3C protease, see Enterokinase (EK), HRV-3C (Human Rhinovirus Protease).