| Field | Specification |
|---|---|
| Mfr No | |
| Accession Number | |
| Activity | |
| Alternative Names | CTX, Cltx, MMP-2, annexin 2 |
| 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 | Recombinant, E. coli |
| Species | |
| Storage | |
| Target |
Overview
Chlorotoxin is a research-grade protein/peptide reagent used in research settings. It is commonly applied as a tool reagent related to Chloride channels, MMP-2, and annexin 2 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 Calcium imaging assay.
Key elements and design rationale
- Molecular identity: CAS: 163515-35-3, MW: 3996.7 Da, Formula: C158H248N52O48S11.
- Source / origin: Leiurus quinquestriatus (scorpion).
- Quality attributes: Purity: ≥98% (HPLC); Bioassay tested: Yes; Sterile / endotoxin-free: No.
Modifications
Disulfide bonds between: Cys2-Cys19, Cys5-Cys28, Cys16- Cys33 and Cys20-Cys35
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 chlorotoxin (CTX) is a 36-amino acid peptide, originally isolated from the venom of the giant yellow Israeli scorpion Leiurus quinquestriatus hebraeus. Its primary amino acid sequence shows considerable homology to a class of short insectotoxins.1Initially, CTX was demonstrated as an irreversible inhibitor of small conductance Cl- channels in colonic epithelial cells and Cl- fluxes across glioma cell membranes.2,3 Inhibition of Cl- channels with CTX prevents cell volume changes, and in turn, inhibits tumor cell invasion and migration.4-6Immunohistochemical studies show that CTX specifically and selectively binds to glioma cell lines and to tissue biopsies from patients with various malignant gliomas and other embryonic related tumors of neuroectodermal origin but not to normal brain tissue.These findings have lead to clinical evaluation for the therapeutic and diagnostic use of CTX, a synthetic derivate, in patients with malignant glioma. This derivative of CTX has been shown to selectively label human gliomas in vivo and in vitro and demonstrated all of the known physical and biological activities of the naturally occurring CTX.7,8Further studies on the interaction of CTX with Cl- channels suggest that these effects are indirect; affinity purification with a recombinant CTX identified the matrix metalloproteinase-2 (MMP2) as a CTX binder in glioma cells. The actual receptor for CTX appears to be a protein complex that contains MMP2 and Cl- channel 3 (ClC-3). Binding of CTX induces endocytosis of this complex and hence the ClC-3 channels. This finding might explain the irreversible action of CTX and its relatively slow time course of Cl- channel blockage.9,10
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
- Calcium imaging assay: 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.
Can’t Find What You’re Looking For? We can help you source the best match or customize a recombinant protein solution for your study. Options may include species (human/mouse/rat), protein region/domain (full-length vs fragment), tag or label (His/GST/FLAG/biotin/fluorescent), expression system (E. coli/HEK293/insect), purity grade, formulation (buffer, carrier-free, glycerol-free), activity/functional validation (binding or enzymatic assays), endotoxin level (low-endotoxin for cell-based work), mutants/variants (point mutations, isoforms), and bulk or custom packaging. Click Talk to a Scientist to submit a request form, email us at support@biohippo.com, or explore our Research Services for additional support. Our team will be in contact with you shortly.
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