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CTX, Cltx

An Inhibitor of Chloride Channels

Cat #: STC-460
Alternative Name CTX, Cltx
Lyophilized Powder yes
  • Bioassay Tested
  • Origin Synthetic peptide
    MW: 3995 Da
    Purity: >98% (HPLC)
    Effective concentration 50-600 nM.
    Modifications Disulfide bonds between Cys2-Cys19, Cys5-Cys28, Cys16-Cys33 and Cys20-Cys35. Arg36 – C-terminal amidation.
    Molecular formula C158H249N53O47S11.
    CAS No.: 163515-35-3
    Activity Chlorotoxin blocks small conductance Cl- channels of epithelial cells and also blocks Cl- channels expressed in gliomas1,2.
    1. DeBin, J.A. et al. (1993) Am. J. Physiol. 264, C361.
    2. Soroceanu, L. et al. (1999) J. Neurosci. 19, 5942.
    Shipping and storage Shipped at room temperature. Product as supplied can be stored intact at room temperature for several weeks. For longer periods, it should be stored at -20°C.
    Solubility Any other aqueous buffer. Centrifuge all product preparations before use (10000 x g 5 min).
    Storage of solutions Up to two week at 4°C or three months at -20°C.
    Our bioassay
    • Alomone Labs Chlorotoxin inhibits Ca2+-activated Cl- currents.
      Alomone Labs Chlorotoxin inhibits Ca2+-activated Cl- currents.
      Inhibition of Ca2+-activated Clcurrents by Chlorotoxin (#STC-460) in human R2 astrocyte cell line. The data are taken from three experiments and the calculated IC50 was 68 nM.
    References - Scientific background
    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) Neuroscience 83, 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.
    Scientific 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.1

    Initially, 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.4-6

    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 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.7,8

    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 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

    Target Chloride channels
    Peptide Content: 100%
    Last update: 06/11/2022

    Chlorotoxin (#STC-460) is a highly pure, synthetic, and biologically active peptide toxin.

    For research purposes only, not for human use
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