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    • Influenza Hemagglutinin (HA) Peptide: High-Purity Epitope...

    2026-01-08

    Influenza Hemagglutinin (HA) Peptide: High-Purity Epitope Tag for Protein Detection and Purification

    Executive Summary: Influenza Hemagglutinin (HA) Peptide is a synthetic nine-amino acid epitope (YPYDVPDYA) derived from the influenza virus hemagglutinin protein, serving as a robust molecular tag for protein detection and purification (APExBIO). The HA tag peptide enables highly specific and competitive binding to anti-HA antibodies, facilitating efficient immunoprecipitation and elution workflows (LabPe). Its high solubility in DMSO (≥55.1 mg/mL), ethanol (≥100.4 mg/mL), and water (≥46.2 mg/mL) provides flexibility across diverse experimental buffers. Purity exceeds 98%, confirmed by HPLC and mass spectrometry, ensuring reproducibility. Proper storage at -20°C is required for stability; long-term storage of solutions is not recommended (APExBIO).

    Biological Rationale

    The HA tag peptide was engineered from the human influenza hemagglutinin protein, specifically the epitope region that is strongly recognized by monoclonal anti-HA antibodies (LabPe). This nine-residue sequence (YPYDVPDYA) is not found in most endogenous proteins, minimizing off-target interactions. The HA tag is used to facilitate detection, isolation, and analysis of tagged fusion proteins in complex biological samples. It is frequently employed in studies of protein-protein interactions, post-translational modifications, and signal transduction pathways, including those involving ubiquitination and E3 ligases (Angiotensin 1-2-1-9). The adoption of the HA tag allows for rapid and scalable workflows in both prokaryotic and eukaryotic systems.

    Mechanism of Action of Influenza Hemagglutinin (HA) Peptide

    The Influenza Hemagglutinin (HA) Peptide functions as an epitope tag by mimicking the antigenic region of the influenza HA protein. When fused to a target protein, the HA tag is accessible to anti-HA antibodies, enabling immunoprecipitation or affinity capture of the tagged protein. The synthetic free HA peptide can be used to competitively displace HA-tagged proteins from antibody complexes, allowing gentle and specific elution without denaturation (Olaparib.net). High-affinity anti-HA antibodies (e.g., clone 12CA5) recognize the linear YPYDVPDYA sequence, ensuring specificity. The tag does not typically interfere with protein folding or function due to its small size. In immunoprecipitation assays, the HA peptide can be added at concentrations sufficient to outcompete the HA-tagged fusion protein for antibody binding, enabling efficient recovery (https://www.apexbt.com/influenza-hemagglutinin-ha-peptide.html). Solubility in water, DMSO, and ethanol allows use in various buffers and conditions.

    Evidence & Benchmarks

    • HA peptide sequence (YPYDVPDYA) is derived from the human influenza virus hemagglutinin protein (UniProt: P03437) (UniProt P03437).
    • Purity of commercial HA peptide (A6004) exceeds 98% as confirmed by HPLC and mass spectrometry (APExBIO).
    • Solubility benchmarks: ≥55.1 mg/mL in DMSO, ≥100.4 mg/mL in ethanol, ≥46.2 mg/mL in water at 25°C (APExBIO).
    • The HA tag enables specific detection and purification of fusion proteins in cell lysates, with minimal cross-reactivity (LabPe).
    • Competitive elution of HA-tagged proteins using synthetic HA peptide is validated in immunoprecipitation and pull-down assays (Dong et al., 2025).
    • HA-tagged proteins are routinely used in studies of post-translational modifications, such as ubiquitination, including in the investigation of PRMT5 and NEDD4L interactions (Dong et al., 2025).

    Applications, Limits & Misconceptions

    The Influenza Hemagglutinin (HA) Peptide is widely used for:

    • Protein detection via Western blot, ELISA, and flow cytometry (APExBIO).
    • Affinity purification and immunoprecipitation of HA-tagged proteins (Olaparib.net).
    • Elution of HA fusion proteins from anti-HA antibody or magnetic bead complexes.
    • Studying protein-protein interactions and post-translational modifications (e.g., ubiquitination) (Angiotensin 1-2-1-9).

    Common Pitfalls or Misconceptions

    • The HA tag sequence does not provide functional activity beyond serving as an epitope; it does not confer enzymatic or structural properties.
    • Not all anti-HA antibodies exhibit equal affinity; validation with the specific clone is recommended for each application.
    • Overexpression or improper folding of HA-tagged proteins may hinder antibody accessibility to the tag.
    • HA peptide is not suitable for in vivo therapeutic use; it is intended for research applications only.
    • Long-term storage of peptide solutions can lead to degradation; peptides should be stored desiccated at -20°C.

    For deeper mechanistic insight, see LabPe (reviews biochemical rationale), Olaparib.net (details high purity and solubility), and Angiotensin 1-2-1-9 (translational relevance). This article extends previous works by providing benchmark data and clarifying limits for competitive elution in ubiquitination studies.

    Workflow Integration & Parameters

    Integration of the Influenza Hemagglutinin (HA) Peptide into laboratory workflows requires attention to several parameters:

    • Optimal concentration for elution is typically 100–400 μg/mL in the elution buffer, but should be empirically determined.
    • Peptide should be freshly reconstituted in compatible solvent (water, DMSO, or ethanol) immediately prior to use.
    • Buffer composition (pH 7.4–8.0, 50–150 mM NaCl) should be compatible with both the antibody and the target protein.
    • Store lyophilized peptide at -20°C in a desiccated environment for maximal stability (APExBIO).
    • Do not freeze and thaw peptide solutions repeatedly.

    The A6004 kit from APExBIO provides high-purity, sequence-verified HA peptide suitable for these applications (Influenza Hemagglutinin (HA) Peptide product page).

    Conclusion & Outlook

    The Influenza Hemagglutinin (HA) Peptide tag remains a gold standard for protein detection and purification in molecular biology and biochemistry. Its high specificity, solubility, and purity support reliable results in immunoprecipitation and protein-protein interaction studies, including advanced research on post-translational modifications such as ubiquitination (Dong et al., 2025). Ongoing improvements in tag-antibody systems and workflow integration will further consolidate its role in translational research. APExBIO continues to support this field with rigorously quality-controlled HA peptide reagents for experimental reproducibility and scientific advancement.