| Field | Specification |
|---|---|
| Mfr No | |
| Accession Number | |
| Activity | |
| Alternative Names | PcTx-1, PcTx1, π-Theraphotoxin-Pc1a, Psalmotoxin 1 |
| Cas No. | |
| 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
Psalmotoxin-1 is a research-grade protein/peptide reagent used in research settings. It is commonly applied as a tool reagent related to ASIC1a 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, Electrophysiology.
Key elements and design rationale
- Molecular identity: CAS: 316808-68-1, MW: 4689.5 Da, Formula: C200H312N62O57S6.
- Source / origin: Psalmopoeus cambridgei (Trinidad chevron tarantula).
- Quality attributes: Purity: ≥99% (HPLC); Bioassay tested: Yes; Sterile / endotoxin-free: No.
Modifications
Disulfide bonds between: Cys3-Cys18, Cys10-Cys23 and Cys17-Cys33
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
Native Psalmotoxin1 (PcTx1) is a 40-amino acid toxin originally isolated from the venom of the South American tarantula Psalmopoeus cambridgei.1PcTX1 is characterized by the unusual quadruplet Lys25-Arg26-Arg27-Arg28, which probably forms a strongly positive "patch" at the surface of the toxin molecule, constituting an area that is a strong candidate for channel binding site recognition. The molecular scaffold of PcTX1 is likely to be similar to that previously described for both cone snail and spider toxins5,6 and comprises a triple-stranded antiparallel β-sheet structure reticulated by three disulfide bridges.1PcTx1 potently (IC50 = 0.9 nM) and specifically blocks a particular subclass of H+-gated cation channels, the Acid-sensing ion channels 1a (ASIC1a) and is able to discriminate between the two splice variant subtypes and not block the ASIC1b channel (which differs only in its N-terminal sequence). Moreover, PcTX1 loses its capacity to block ASIC1a as soon as this subunit is associated with another member of the family (ASIC2a or ASIC3).1The ASICs are abundant in the brain and spinal cord neurons and are implicated in pain sensation, ischemic stroke mechanosensation, learning and memory.2,3 In acute and neuropathic pain models, specific blockage of ASIC1a with PcTx1 results in analgesic effects working upstream of the opiate receptors.4Using an iodinated form of the toxin, the binding for the PcTX1 site identifies at the cysteine-rich domains I and II (CRDI and CRDII) of the extracellular loop of ASIC1a. A disulphide bridge between domains 1 and 4 of the channel supports a close relationship between the CRDI4-CRDII domain, where PcTx1 acts, and the post-M1 region, the binding site for the proton.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.
- 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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