Chlorotoxin

CTX, Cltx
An Inhibitor of Chloride Channels
    Cat #: RTC-450
    Sizes: 0.1 mg, 0.5 mg, 1 mg, 5 mg
  • Lyophilized Powder
  • Bioassay Tested
  • Shipped at Room Temp.
  • 100% Net Peptide
  • Origin Leiurus quinquestriatus quinquestriatus (Egyptian scorpion).
    Source: Recombinant, E. coli
    MW: 3996 Da.
    Purity >98%.
    Effective concentration 50-600 nM.
    Sequence MCMPCFTTDHQMARKCDDCCGGKGRGKCYGPQCLCR.
    Modifications Disulfide bonds between Cys2-Cys19, Cys5-Cys28, Cys16- Cys33 and Cys20-Cys35.
    Structure
    Molecular formula C158H249N53O47S11.
    CAS number 163515-35-3.
    Activity Chlorotoxin blocks small conductance Clchannels of epithelial cells and also blocks Cl- channels expressed in gliomas1,2.
    Storage before reconstitution Lyophilized powder can be stored intact at room temperature for several weeks. For longer periods, it should be stored at -20°C.
    Reconstitution Any aqueous buffer. Centrifuge all product preparations before use (10000 x g 5 min).
    Storage after reconstitution Up to four weeks at 4°C or three months at -20°C.
    Our bioassay
    Alomone Labs Chlorotoxin inhibits Ca2+-activated Cl- currents.
    Inhibition of Ca2+-activated Clcurrents by Chlorotoxin (#RTC-450) in human R2 astrocyte cell line. The data is taken from three experiments and the calculated IC50 was 68 nM.
    References
    1. DeBin, J. A. and Strichartz, G. R. (1991) Toxicon 29, 1403.
    2. DeBin, J.A. et al. (1993) Am. J. Physiol. 264, C361.
    3. Soroceanu, L. et al. (1999) J. Neurosci. 19, 5942.
    4. Ullrich, N. et al. (1998) Neuroscience83,1161.
    5. Ullrich, N. et al. (1996) Neuroreport 7, 1020.
    6. Soroceanu, L. et al. (1998) Cancer Res. 58, 4871.
    7. Lyons, S. A. et al. (2002) Glia 39, 162.
    8. Deshane, J. et al. (2003) J. Biol. Chem278, 4135.
    9. McFerrin, M. B. and Sontheimer, H. (2006) Neuron. Glia. Biol. 2, 39.
    Target: Chloride channels
    Net Peptide Content: 100%
    Last update: 25/12/2017

    Native Chlorotoxin (CTX) is a 36-amino acid peptide, originally isolated from the venom of the giant yellow Israeli scorpion Leiurus quinquestriatus hebraeus. Primary amino acid sequence shows considerable homology to a class of short insectotoxins.1

    Initially, CTX has been demonstrated as an irreversible inhibitor of small conductance Clchannels 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.4-6

    Immunohistochemical 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.

    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.7,8

    Further 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 CTX binder in glioma cells. The actual receptor for CTX appears to be a protein complex that contains MMP2 and ClChannel-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 Clchannel blockage.9,10

    Alomone Labs is pleased to offer Chlorotoxin (#RTC-450), expressed in E. coli and purified to homogeneity.

    For research purposes only, not for human use

    For a list of product citations in the literature, see “product citations” below. If you know of additional relevant citations for this product, please let us know.