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Chlorotoxin

  CAS No.: 163515-35-3   Cat No.: BADC-00153   Purity: >95% 4.5  

Chlorotoxin (Cltx) is a neurotoxin that was originally isolated from the venom of Leiurus quinquestriatus. Chlorotoxin is a specific ligand of glioma cells. Chlorotoxin binds to Cl- channels (small conductance epithelial chloride channels) in the brain and spinal cord and inhibits Cl- influx.

Chlorotoxin

Structure of 163515-35-3

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Category
ADC Cytotoxin
Molecular Formula
C29H37N5O9S1
Molecular Weight
599.64
Shipping
Room temperature
Storage
Store at -20°C

* For research and manufacturing use only. We do not sell to patients.

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1 mg $519 In stock

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Popular Publications Citing BOC Sciences Products
IUPAC Name
2-[(1R,4R,5aR,8aS,9R,12S,17aS,18S,20aS,21R,24S,27S,30S,33S,36S,39S,42S,45S,48S,51S,54R,59R,62S,65S,74S,77R,80S,86S,92S)-51,80,92-tris(4-aminobutyl)-5a-[[(2S)-1-amino-5-carbamimidamido-1-oxopentan-2-yl]carbamoyl]-9-[[(2S)-2-amino-4-methylsulfanylbutanoyl]amino]-39,62-bis(3-amino-3-oxopropyl)-24-benzyl-48,86-bis(3-carbamimidamidopropyl)-20a,33-bis(carboxymethyl)-27,30-bis[(1R)-1-hydroxyethyl]-74-[(4-hydroxyphenyl)methyl]-36-(1H-imidazol-4-ylmethyl)-45-methyl-8a-(2-methylpropyl)-12,42-bis(2-methylsulfanylethyl)-a,3,7a,10,10a,13,15a,18a,19,21a,22,25,28,31,34,37,40,43,46,49,52,61,64,70,73,76,79,82,85,88,91,94,97-tritriacontaoxo-2a,3a,6,7,12a,13a,56,57-octathia-2,6a,9a,11,14,16a,19a,20,22a,23,26,29,32,35,38,41,44,47,50,53,60,63,69,72,75,78,81,84,87,90,93,96,99-tritriacontazahexacyclo[57.41.10.84,54.421,77.014,18.065,69]docosahectan-17a-yl]acetic acid
Canonical SMILES
CC1C(=O)NC(C(=O)NC(C(=O)NC2CSSCC3C(=O)NC(C(=O)NC(CSSCC4C(=O)NCC(=O)NCC(=O)NC(C(=O)NCC(=O)NC(C(=O)NCC(=O)NC(C(=O)NC(CSSCC(C(=O)NC(C(=O)NC(C(=O)NC(C(=O)NC(C(=O)NC(C(=O)NC(C(=O)NC(C(=O)N1)CCSC)CCC(=O)N)CC5=CNC=N5)CC(=O)O)C(C)O)C(C)O)CC6=CC=CC=C6)NC(=O)C7CCCN7C(=O)C(NC(=O)C(CSSCC(C(=O)N4)NC(=O)C(NC(=O)C(NC2=O)CC(=O)O)CC(=O)O)NC(=O)C(CCSC)N)CCSC)C(=O)NC(C(=O)NCC(=O)N8CCCC8C(=O)NC(C(=O)N3)CCC(=O)N)CC9=CC=C(C=C9)O)CCCCN)CCCNC(=N)N)CCCCN)C(=O)NC(CCCNC(=N)N)C(=O)N)CC(C)C)CCCCN)CCCNC(=N)N
InChI
InChI=1S/C158H249N53O47S11/c1-77(2)55-96-138(241)205-105(144(247)186-86(125(165)228)28-18-47-173-156(166)167)70-264-262-68-103-131(234)177-63-115(217)176-64-116(218)183-87(25-12-15-44-159)128(231)178-65-117(219)184-88(29-19-48-174-157(168)169)129(232)179-66-118(220)185-89(26-13-16-45-160)133(236)202-107-72-267-269-75-110-149(252)195-98(56-81-23-10-9-11-24-81)143(246)208-124(80(5)213)154(257)209-123(79(4)212)153(256)199-102(61-122(226)227)141(244)196-99(58-83-62-172-76-181-83)139(242)189-92(37-39-113(163)215)136(239)190-94(42-53-260-7)132(235)182-78(3)126(229)187-91(30-20-49-175-158(170)171)134(237)188-90(27-14-17-46-161)135(238)203-108(73-266-265-71-106(146(249)193-96)204-137(240)93(38-40-114(164)216)191-151(254)111-31-21-50-210(111)119(221)67-180-130(233)97(194-147(107)250)57-82-33-35-84(214)36-34-82)148(251)198-100(59-120(222)223)140(243)197-101(60-121(224)225)142(245)206-109(150(253)201-103)74-268-263-69-104(200-127(230)85(162)41-52-259-6)145(248)192-95(43-54-261-8)155(258)211-51-22-32-112(211)152(255)207-110/h9-11,23-24,33-36,62,76-80,85-112,123-124,212-214H,12-22,25-32,37-61,63-75,159-162H2,1-8H3,(H2,163,215)(H2,164,216)(H2,165,228)(H,172,181)(H,176,217)(H,177,234)(H,178,231)(H,179,232)(H,180,233)(H,182,235)(H,183,218)(H,184,219)(H,185,220)(H,186,247)(H,187,229)(H,188,237)(H,189,242)(H,190,239)(H,191,254)(H,192,248)(H,193,249)(H,194,250)(H,195,252)(H,196,244)(H,197,243)(H,198,251)(H,199,256)(H,200,230)(H,201,253)(H,202,236)(H,203,238)(H,204,240)(H,205,241)(H,206,245)(H,207,255)(H,208,246)(H,209,257)(H,222,223)(H,224,225)(H,226,227)(H4,166,167,173)(H4,168,169,174)(H4,170,171,175)/t78-,79+,80+,85-,86-,87-,88-,89-,90-,91-,92-,93-,94-,95-,96-,97-,98-,99-,100-,101-,102-,103-,104-,105-,106-,107-,108-,109-,110-,111-,112-,123-,124-/m0/s1
InChIKey
QPAKKWCQMHUHNI-GQIQPHNSSA-N
Sequence
MC(1)MPC(2)FTTDHQMARKC(3)DDC(1)C(4)GGKGRGKC(2)YGPQC(3)LC(4)R
Solubility
Soluble in DMSO
Appearance
White lyophilized solid
Shipping
Room temperature
Storage
Store at -20°C
In Vitro
In in vitro study, chlorotoxin (CTX) inhibits the expression of ERα in breast cancer cells. CTX can directly bind to ERα and change the protein secondary structure of its LBD domain, thereby inhibiting the ERα signaling pathway.
In Vivo
Chlorotoxin (CTX) can inhibit breast cancer cell proliferation, migration, and invasion through ERα/VASP signaling pathway. In in vivo study, CTX significantly inhibits growth of ER overexpressing breast tumor can target ER overexpressing breast tumors in vivo. Mouse studies revealed that chlorotoxin:Cy5.5 (CTX:Cy5.5) has favorable biodistribution and toxicity profiles.Chlorotoxin:Cy5.5 (CTX:Cy5.5) has the potential to fundamentally improve intraoperative detection and resection of malignancies.
NCT NumberCondition Or DiseasePhaseStart DateSponsorStatus
NCT00379132Breast CancerPhase 12009-03-31TransMolecularCompleted
NCT00683761Malignant GliomaPhase 1, Phase 22009-07-17TransMolecularUnknown Verified July 2009 by TransMolecular. Recruitment status was Active, not recruiting
NCT00591058Malignant GliomaPhase 12009-07-17TransMolecularUnknown Verified July 2009 by TransMolecular. Recruitment status was Active, not recruiting
NCT00114309Malignant GliomaPhase 22009-04-03TransMolecularUnknown Verified April 2009 by TransMolecular. Recruitment status was Active, not recruiting
NCT04214392Recurrent GlioblastomaPhase 12021-06-15City of Hope Medical CenterRecruiting

Chlorotoxin is a 36-amino-acid peptide derived from scorpion venom and has emerged as a potential ADC cytotoxin in the design of antibody-drug conjugates. As an ADC payload, Chlorotoxin selectively binds to matrix metalloproteinase-2 (MMP-2) and chloride channels overexpressed on tumor cells, enabling targeted delivery of cytotoxic effects. Its high tumor selectivity and low systemic toxicity make it a promising candidate for precision oncology applications.

Within antibody-drug conjugates, Chlorotoxin can be conjugated to monoclonal antibodies or other targeting scaffolds via cleavable or non-cleavable linkers. Upon binding and internalization, the payload mediates inhibition of ion channels and disrupts tumor cell invasiveness and proliferation. This tumor-specific mechanism allows ADCs incorporating Chlorotoxin to deliver cytotoxic or anti-invasive effects directly to malignant cells, minimizing off-target damage and enhancing therapeutic index.

Applications of Chlorotoxin in ADC development include targeting gliomas, neuroblastomas, and other MMP-2 overexpressing solid tumors. Its peptide nature allows chemical modification for enhanced stability, linker compatibility, and conjugation efficiency. Researchers are exploring Chlorotoxin-based ADCs to improve tumor penetration, reduce systemic exposure, and exploit its dual function as both a targeting moiety and cytotoxic agent, supporting the creation of next-generation, precision-targeted antibody-drug conjugates.

1. Glioblastoma multiforme targeted therapy: The Chlorotoxin story
Or Cohen-Inbar, Menashe Zaaroor J Clin Neurosci . 2016 Nov;33:52-58. doi: 10.1016/j.jocn.2016.04.012.
Glioblastoma multiforme (GBM) is the most common malignant primary brain neoplasm having a mean survival of <24months. Scorpion toxins are considered promising cancer drug candidates, primarily due to the discovery of hlorotoxin, derived from the venom of the Israeli yellow scorpion. This intriguing short peptide of only 36 amino-acids length and tight configuration, possess the ability to bind to GBM cells in a grade-related manner with ~100% of GBM cells staining positive and no cross reactivity to normal brain. Chlorotoxin has an anti-angiogenic effect as well. Molecular targets for Chlorotoxin include voltage gated chloride channels (GCC), calcium-dependent phospholipid-binding protein Annexin-2, and the inducible extracellular enzyme Matrix Metalloproteinase-2 (MMP-2). Of all its targets, MMP-2 seems to bear the most anti-neoplastic potential. Chlorotoxin is a promising tumortargeting peptide. Its small size and compact shape are convenient for intracranial delivery. We present a short discussion on Chlorotoxin. The structure, biological activity, molecular targets and possible clinical role of Chlorotoxin are discussed. Chlorotoxin can be utilized as a targeting domain as well, attaching different effector functions to it. Clinical applications in GBM therapy, intraoperative imaging, nano-probes and nano-vectors based technology; targeted chemotherapy and immunotherapy are discussed as well. Chlorotoxin is likely to play a significant role in effective GBM immunotherapy in the future.
2. 131I-Chlorotoxin
The MICAD Research Team
Chlorotoxin (CTX) is a neurotoxin comprising 36 amino acids and is isolated from the venom ofLeiurus quinquestriatus, a scorpion of the Buthidae family. A characteristic feature of the peptide is the four disulfide bonds that give it a tight tertiary structure and a single tyrosine residue that can be iodinated. Originally, CTX was described as a calcium channel blocker (1). Later, selective and specific binding of CTX to glioma cells was demonstrated by immunochemical techniques, and radiolabeled CTX was shown to bind only to tumor cells in a mouse xenograft glioma tumor model (1). On the basis ofin vitrostudies, CTX was discovered to bind only to malignant (glioma) and not normal (glial) cells, indicating that the toxin had a binding specificity for embryologically related tumors, particularly those of neuroectodermal origin (2). Using a recombinant form of the toxin, it was shown that CTX binds to and reduces the activity of a matrix metalloproteinase (MMP) that is associated with and indirectly regulates functioning of the chloride channels on cell membranes (3, 4). Deshane et al. showed that isoform 2 of the MMP (MMP2) was the specific cellular receptor for CTX and that the ligand did not bind to the other MMPs also expressed on the glioma cells (4). In otherin vitrostudies it was shown that CTX reduced the migration ability of glioma cells through tight extracellular spaces in the brain tissue by inhibition of the MMP2, because this prevented the cells from shrinking and releasing from the extracellular matrix (5).The MMP2 enzyme activity was observed to be significantly elevated in malignant glioma cells compared to low-grade glioma and normal brain tissues, and the upregulation correlated with the malignant progression of human gliomasin vivo(6). In the same study, which used immunohistochemical techniques, MMP2 was shown to be localized only in the cells and vasculature of malignant glioma tumors. These observations explained the specificity and selectivity of CTX binding to the malignant glioma tumors observed by the various investigators. Currently, resection of the tumor is the only effective treatment for glioma, but the tumor often reappears at the same spot or close to it because not all neoplastic cells can be completely removed during surgery.Because of its specificity and selectivity for glioma cells, a synthetic version of CTX, TM-601, was generated either by production inEscherchia colior by chemical synthesis (2, 4, 7). The peptide has been radiolabeled with radioactive iodine (131I) to obtain131I-TM601 and used for preclinical and clinical imaging and radiotherapy of malignant glioma (8, 9). The iodinated peptide is currently beingevaluated in clinical trialsin the United States for the treatment of solid tumors or recurrent high-grade gliomas in humans (10).
3. Chlorotoxin-conjugated nanoparticles for targeted imaging and therapy of glioma
Jinhua Zhao, Xiangyang Shi, Lingzhou Zhao Curr Top Med Chem . 2015;15(13):1196-208. doi: 10.2174/1568026615666150330110822.
This review reports the recent advances in chlorotoxin (CTX)-targeted nanoparticles (NPs) for imaging and therapy of glioma. CTX has been identified as a targeting ligand to specifically bind to glioma. Through different conjugation approaches, CTX can be conjugated onto iron oxide NPs, quantum dots, and rare-earth upconversion NPs for targeted magnetic resonance and fluorescence imaging of glioma. Likewise, CTX-conjugated NPs can also be used as a carrier system to load anticancer drugs or therapeutic genes for targeted chemotherapy or gene therapy of glioma, respectively. Some of the key developments in this area of research will be introduced in detail. Challenges and future perspectives in the development of CTX-conjugated NPs will be discussed.

What is Chlorotoxin?

Chlorotoxin is a peptide-based cytotoxin derived from scorpion venom and is utilized in ADCs for selective targeting. It binds specifically to chloride channels or matrix metalloproteinase-2, facilitating targeted delivery of cytotoxic payloads.

29/1/2022

Could you kindly explain how Chlorotoxin is applied in ADC development?

Chlorotoxin is conjugated to antibodies to selectively direct cytotoxic agents to cells expressing relevant channels or enzymes. This targeted approach enhances therapeutic efficiency while minimizing effects on non-target tissues.

13/9/2020

We are interested in knowing which linkers are appropriate for Chlorotoxin ADCs.

Chlorotoxin can be conjugated via cleavable linkers for intracellular payload release or non-cleavable linkers for improved systemic stability. Linker choice is guided by desired release kinetics and pharmacological profile.

25/12/2022

Could you please let me know what precautions should be observed when handling Chlorotoxin?

Due to its biological activity, Chlorotoxin must be handled using standard biosafety procedures, including PPE and containment measures, to prevent accidental exposure during conjugation and experimental workflows.

3/10/2021

Good afternoon! What advantages do Chlorotoxin ADCs offer?

Chlorotoxin ADCs enable targeted cytotoxicity toward specific cellular markers, improving therapeutic indices and allowing more precise preclinical research. They facilitate selective drug delivery in oncology and neurological disease models.

9/27/2019

— Dr. Kevin Wallace, Senior Scientist (USA)

Chlorotoxin from BOC Sciences arrived with excellent purity, supporting our ADC projects seamlessly.

25/12/2022

— Dr. Jonathan Reed, Oncology Scientist (USA)

We sourced Chlorotoxin from BOC Sciences for our tumor-targeting studies. The compound showed remarkable stability and bioactivity, making our experimental design far more reliable.

9/27/2019

— Dr. Hans Bauer, Medicinal Chemist (Germany)

Fast delivery and detailed QC documentation for Chlorotoxin ensured project continuity.

3/10/2021

— Dr. Helen Brooks, Senior Research Scientist (UK)

Chlorotoxin from BOC Sciences integrated smoothly into our targeting experiments. The compound displayed excellent consistency across multiple assay conditions, giving us confidence in data reproducibility.

29/1/2022

— Dr. Richard Moore, Lead Scientist (USA)

High-purity Chlorotoxin and timely delivery boosted our ADC assay performance.

— Dr. Michael Turner, Biomedical Research Scientist (USA)

We needed Chlorotoxin quickly for our peptide-targeting research, and BOC Sciences delivered on schedule. The compound maintained high purity and was supported by transparent analytical data.

13/9/2020

The molarity calculator equation

Mass (g) = Concentration (mol/L) × Volume (L) × Molecular Weight (g/mol)

The dilution calculator equation

Concentration (start) × Volume (start) = Concentration (final) × Volume (final)

This equation is commonly abbreviated as: C1V1 = C2V2

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