V5 Epitope Tag Peptide (GKPIPNPLLGLDST): Benchmarks & Molecular Use

Executive Summary: The V5 Epitope Tag Peptide (SKU: A6005) is a 14-amino acid sequence (GKPIPNPLLGLDST) derived from paramyxovirus simian virus 5. It is recognized by high-affinity anti-V5 antibodies, enabling reliable detection and purification of tagged proteins (Miyoshi et al., 2021). The tag demonstrates minimal interference with protein function, robust solubility in DMSO (≥71.08 mg/mL), ethanol (≥107.2 mg/mL), and water (≥55.4 mg/mL), and is compatible with multiplexed molecular workflows. APExBIO’s V5 tag product is validated for Western blot, immunoprecipitation, and advanced imaging, outperforming traditional tags in sensitivity and flexibility (see related review).

Biological Rationale

The V5 Epitope Tag Peptide is designed for molecular biology applications requiring specific protein labeling. It originates from the P and V proteins of simian virus 5 (SV5), a paramyxovirus, providing a sequence not found in most expression hosts. This minimizes cross-reactivity with endogenous proteins (Miyoshi et al., 2021). The tag is genetically fused to proteins of interest at the DNA level, enabling post-translational identification with high-affinity monoclonal anti-V5 antibodies. Its small size (14 residues) reduces the likelihood of steric hindrance or disruption of protein structure and function. The tag’s unique sequence ensures specificity in immunodetection and supports multiplexed experiments with orthogonal tags. Peer-reviewed studies confirm the V5 tag’s compatibility with a variety of host cell types and its utility in recombinant virus construction (see comparative discussion).

Mechanism of Action of V5 Epitope Tag Peptide

The V5 tag functions by providing a unique, linear epitope that is accessible to anti-V5 antibodies in denatured or native protein conformations. After fusion to a target protein, the tag is expressed as part of the recombinant protein. High-specificity monoclonal antibodies or Fab fragments, such as those screened for fast dissociation rates (t_1/2 = 0.98–2.2 s), bind the tag efficiently without significant off-target recognition (Miyoshi et al., 2021). The antibody-epitope complex allows for detection (via Western blot, ELISA, immunofluorescence), affinity purification, or imaging-based localization. The tag’s hydrophilicity and solubility facilitate its use in diverse buffers and solvents. APExBIO supplies the V5 Epitope Tag Peptide as a solid, to be reconstituted as required for experimental protocols.

Evidence & Benchmarks

• The GKPIPNPLLGLDST sequence is derived from simian virus 5 and is not found in most eukaryotic proteomes, reducing non-specific background (Miyoshi et al., 2021).
• Anti-V5 monoclonal antibodies exhibit rapid yet specific binding (dissociation t_1/2 of 0.98–2.2 s) in single-molecule assays, supporting real-time imaging applications (Miyoshi et al., 2021).
• The peptide is soluble at ≥71.08 mg/mL in DMSO, ≥107.2 mg/mL in ethanol, and ≥55.4 mg/mL in water (APExBIO product specification: A6005).
• V5-tagged proteins can be detected using Western blot, immunoprecipitation, and advanced microscopy, with minimal functional interference observed in recombinant virus studies (review article).
• The V5 tag supports multiplexed detection in combination with other epitope tags for high-throughput workflows (Miyoshi et al., 2021).

Applications, Limits & Misconceptions

The V5 Epitope Tag Peptide is broadly applicable for protein tagging in mammalian, insect, yeast, and bacterial expression systems. It supports reliable detection in Western blotting, immunoprecipitation, ELISA, protein purification, and super-resolution imaging. The tag is compatible with both N- and C-terminal protein fusions. In recombinant virus research, V5 tagging enables differentiation of viral proteins from host backgrounds (mechanistic overview). Compared to larger tags (e.g., GFP), the V5 tag imposes less steric hindrance, preserving native protein function.

Common Pitfalls or Misconceptions

• Not suitable for diagnostic/therapeutic uses: The V5 tag is intended for research applications only; clinical or therapeutic deployment is not validated (APExBIO).
• May not be recognized in certain denatured conditions: Excessive harsh denaturation can mask the epitope, reducing antibody binding efficiency.
• Tag position matters: Fusion at internal sites or within structured domains can interfere with tag accessibility.
• Overexpression artifacts: High-level expression of V5-tagged proteins may alter cellular localization or protein stability unrelated to the tag itself.
• Cross-reactivity with low-specificity antibodies: Use only validated monoclonal anti-V5 antibodies to minimize non-specific detection (benchmark study).

Workflow Integration & Parameters

To utilize the V5 Epitope Tag Peptide, encode the tag sequence at the desired fusion site during recombinant DNA design. For protein detection, employ high-affinity monoclonal anti-V5 antibodies at recommended dilutions (product page). Immunoprecipitation protocols should use non-denaturing buffers to preserve epitope accessibility. For imaging, fluorescently labeled Fab fragments enable live-cell super-resolution microscopy with rapid antibody turnover, as validated in dual-view inverted selective plane illumination microscopy (diSPIM) (Miyoshi et al., 2021). Store the peptide desiccated at -20°C for long-term stability. Reconstitution should use sterile solvents at concentrations appropriate for the intended workflow (e.g., ≥55.4 mg/mL in water for immunoassays). For further troubleshooting or advanced applications, APExBIO provides technical support and peer-reviewed protocols.

This article extends recent coverage, such as the in-depth analysis on multiplex detection, by directly correlating solubility and benchmarked antibody kinetics, and updates the mechanistic overview presented in this mechanistic summary by integrating new evidence from single-molecule microscopy.

Conclusion & Outlook

The V5 Epitope Tag Peptide (GKPIPNPLLGLDST) is established as a robust, minimally invasive protein tag for research applications. Its validated specificity, solubility, and compatibility with advanced detection platforms make it a preferred choice for multiplexed molecular workflows. Ongoing advances in antibody engineering and imaging platforms are expected to further expand the tag’s application range. For detailed product specifications and ordering, consult the APExBIO V5 Epitope Tag Peptide page.