| Field | Specification |
|---|---|
| Mfr No | |
| Accession Number | |
| Activity | |
| Alternative Names | Delta-theraphotoxin-Hm1a, Delta-TRTX-Hm1a, Heteroscodratoxin-1, HmTx1, Kappa-theraphotoxin-Hm1a, Kappa-TRTX-Hm1a, KV2, KV4 channels |
| Concentration | |
| Form | Lyophilized |
| Formulation | |
| Gene ID | |
| Molecular Weight | |
| Product Type | |
| Purity | |
| Reconstitution | |
| Source | Synthetic peptide |
| Species | |
| Storage | |
| Target |
Overview
Hm1a Toxin is a research-grade protein/peptide reagent used in research settings. It is commonly applied as a tool reagent related to NaV1.1, KV2, KV4 channels biology and/or assay development. It is supplied in Lyophilized format to support flexible downstream use in RUO workflows. Researchers commonly pair it with applications such as Electrophysiology.
Key elements and design rationale
- Molecular identity: MW: 3997 Da, Formula: C170H239N47O54S6.
- Source / origin: Heteroscodra maculata (Togo starburst tarantula) (Togo starburst baboon spider).
- Quality attributes: Purity: ≥98% (HPLC); Bioassay tested: Yes; Sterile / endotoxin-free: No.
Modifications
Disulfide bonds between: Cys2-Cys16, Cys9-Cys21 and Cys15-Cys28
When used as a biochemical or pharmacological tool, results are best interpreted relative to the experimental system (species, expression level, and assay readout) and with appropriate negative and competition-style controls where relevant. This product is intended for research use only.
Biological background
Delta-theraphotoxin-Hm1a (Hm1a) is a peptide toxin originally isolated from Heteroscodra maculate tarantula venom. Initially described as a moderate-affinity KV4.1 blocker¹, later studies confirmed it primarily targets NaV1.1 voltage-gated sodium channels²,3. It interacts with extracellular loops connecting transmembrane segments 1-2 and 3-4 in domain IV voltage sensor of the channel to inhibit NaV1.1 fast inactivation2,3. Hm1a inhibits human NaV1.1 channel inactivation expressed in Xenopus oocytes with EC50 value of 38 ± 6 nM. Recent studies show Hm1a restores interneuron firing in Scn1a+/- mice, improving inhibition in Dravet Syndrome models⁴. Electrophysiology confirms it prolongs NaV1.1 activation with minimal effects on NaV1.2 and Na1.6⁵,⁶. NaV1.1 channel is a therapeutic target for brain disorders, such as epilepsy, Alzheimer's disease, and autism. It also contributes to mechanical pain by regulating excitability in a specific subset of sensory neurons within the peripheral nervous system. Hm1a is a valuable tool for neuroscience and pharmacology research⁴-⁷.
Research relevance and current trends
- Using high-specificity ligands, toxins, and engineered peptides to dissect closely related receptor/channel subtypes and signaling microdomains.
- Pairing labeled (e.g., fluorescent) proteins/peptides with advanced imaging to map surface expression, trafficking, and nanoscale organization.
- Increasing emphasis on reproducibility through standardized characterization (identity, purity, and lot QC) and transparent reporting of reagent attributes.
Common research applications
- Electrophysiology: commonly used to compare signal, binding, or functional readouts across conditions without implying a specific protocol.
Across these use cases, changes in signal or functional readout are generally interpreted as evidence of differences in target abundance, accessibility, or engagement, but alternative explanations (matrix effects, off-target interactions, or assay artifacts) should be considered.
Notes for experimental interpretation
- Assay context matters: binding assays, functional modulation, and detection workflows can yield different readouts even for the same target system.
- Target complexity: closely related family members, splice variants, and post-translational modifications can influence apparent specificity and potency.
- Matrix and sample effects: buffer composition, detergents, and biological matrices may alter stability or apparent activity; interpret with appropriate controls.
- Control concepts: include negative controls and orthogonal validation (e.g., genetic perturbation or alternative reagents) to support robust interpretation.
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Chow, C.Y.
et al. (2020) ACS Pharmacol. Transl. Sci.3, 119.
Escoubas, P.
et al. (2002) Mol. Pharmacol.62, 48.
Osteen, J.D.
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et al. (2017) Proc. Natl. Acad. Sci. U.S.A.114, 6836.
Goff, K.M. and Goldberg, E.M.
(2019) eLife, 8, e46846.
Almog, Y.
et al. (2022) Front Mol Neurosci., 15, 823640.
Mattis, J.
et al. (2022) eLife, 11, e69293.
Mora-Jimenez, L.
et al. (2021) Mol Ther Nucleic Acids, 25, 585-599.
