rChlorotoxin

貨號 Cat. No.: RTC-450
規格 Size: 40 Î¼g 5x40 Î¼g 0.5mg

Description

rChlorotoxin

An Inhibitor of Some Chloride Channels

Product#:

RTC-450

Sizes:

40 mg

5 x 40 mg

0.5 mg

M.W.:

3996.7

Sequence:

MCMPC FTTDH QMARK CDDCC GGKGR GKCYG PQCLC R

Purity:

>98%

Bioassay:

This activity of this lot was tested by its ability to inhibit Ca²⁺ activated Cl^- currents.

Inhibition of Ca²⁺ activated Cl^- currents in an immortalized cell line of human type R2 astrocytes that constiutively express the Cl(Ca) channel. The data is taken from three experiments and the calculated IC₅₀ was 68nM.

References:

1.	DeBin, J. A. and Strichartz, G. R. (1991) Toxicon 29, 1403.
2.	DeBin, J. A. et al. (1993) Am. J. Physiol. 264, 361.
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. (1999) J Neurosci.19, 5942.
7.	Soroceanu, L., et al.. (1998) Cancer Res. 58, 4871.
8.	Lyons, S. A. et al. (2002) Glia 39, 162.
9.	Deshane, J, et al. (2003) J. Biol. Chem. 278, 4135.
10.	McFerrin, M. B. and Sontheimer, H. (2006) Glial Biol 2, 39.

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

Initially, CTX has been demonstrated as an irreversible inhibitor of smallconductance Clchannels in colonic epithelial cells and Clfluxes across glioma cell membranes.^2,3Inhibition of Cl^{?/SUP> channels with CTXprevents cell volume changes, and in turn, inhibits tumorcell invasion and migration.^4-6Immunohistochemicalstudies show that CTX specifically and selectively binds to gliomacell lines and to tissue biopsies from patients withvarious malignant gliomas and other embryonic related tumors of neuroectodermalorigin but not to normalbrain. These findings have lead to clinical evaluation for the therapeuticand diagnostic use of CTX a synthetic derivate in patientswith malignant glioma. This derivative of CTX has been shown to selectivelylabel human gliomas in vivo and in vitro and demonstratedall of the known physical and biological activities of the naturally occurringCTX^.7,8}

Further studieson the interaction of CTX with Cl^{?/SUP> channels suggestthat these effects are indirect; affinitypurification with a recombinant CTX identified the matrixmetalloproteinase-2 (MMP2) as CTX binder in glioma cells. The actual receptor for CTX appears to be a protein complex that contains MMP2 andCl^-Channel-3 (ClC-3). Binding of CTX induces endocytosis of this complexand hence the ClC-3 channels. This finding might explain the irreversible actionof CTX and its relatively slow time course of Cl^?channel blockage.^9,10}

Alomone Labs is pleased to offer rChlorotoxin (rCTX), a recombinant peptide expressed in and extracted from E. coli and purified to homogeneity.

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