| Field | Specification |
|---|---|
| Mfr No | |
| Accession Number | |
| Activity | |
| Alternative Names | Delta-theraphotoxin-Hm1b, Delta-TRTX-Hm1b, δ-theraphotoxin-Hm1b, Nav1.3, Voltage-gated Na+ channels |
| Concentration | |
| Form | Lyophilized |
| Formulation | |
| Gene ID | |
| Molecular Weight | |
| Product Type | |
| Purity | |
| Reconstitution | |
| Solubility | Centrifuge the vial before adding solvent (10,000 x g for 5 minutes) to spin down all the powder to the bottom of the vial. The lyophilized product may be difficult to visualize. Add solvent directly to the centrifuged vial. Tap the vial to aid in dissolving the lyophilized product. Tilt and gently roll the liquid over the walls of the vial. Avoid vigorous vortexing. Light vortexing for up to 3 seconds is acceptable if needed. The product is soluble in pure water at high micromolar concentrations (100 µM - 1 mM). For long-term storage in solution, we recommend preparing a stock solution by dissolving the product in double-distilled water (ddH2O) at a concentration between 100-1000x of the final working concentration. Divide the stock solution into small aliquots and store at -20°C. Before use, thaw the relevant vial(s) and dilute to the desired working concentration in your working buffer. Centrifuge all product preparations before use. It is recommended to prepare fresh solutions in working buffers just before use. Avoid multiple freeze-thaw cycles to maintain biological activity. |
| Source | Synthetic peptide |
| Species | |
| Storage | |
| Target |
Overview
Hm1b Toxin is a research-grade protein/peptide reagent used in research settings. It is commonly applied as a tool reagent related to NaV1.1, Nav1.3, Voltage-gated Na+ 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: 3895.4 Da, Formula: C169H241N45O50S6.
- 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
δ-theraphotoxin-Hm1b (Hm1b) is a 34 amino acid peptidyl toxin originally isolated from the venom of the tarantula, Heteroscodra maculata1. Hm1b acts as a potent and highly selective activator of the voltage-gated sodium (NaV) 1.1 and NaV1.3 channels. This toxin inhibits the inactivation of the human NaV1.1 channel (expressed in HEK293 cells) with an EC value of 12 nM1,2.The Hm1b toxin has a high level of sequence similarity to the Hm1a toxin, which is also a selective and specific activator of NaV1.1 channels. Both toxins are members of the extended family of inhibitor cystine knot (ICK) peptides with C1-C4, C2-C5, and C3-C6 disulfide architecture. In addition, they share secondary structure characteristics, specifically an antiparallel β hairpin. Despite the high degree of sequence similarity between Hm1a and Hm1b, the latter is much more stable in biological fluids2.NaV channels are involved in a wide array of physiological processes and play a fundamental role in normal neurological function, especially in the initiation and propagation of action potentials. NaV1.1 channel has been utilized as a therapeutic target for various brain disorders, including epilepsy, Alzheimer's disease, and autisM The NaV1.1 channel also contributes to mechanical pain by regulating the excitability of a specific subset of sensory neurons within the peripheral nervous systeM
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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Osteen, J.D.
et al. (2016) Nature 534, 494.
Osteen, J.D.
et al. (2016) Nature 534, 494.
Chow, C.Y.
et al. (2020) Biochem. Pharm.181, 113991
