Mu-Conotoxin CnIIIC (XEP-018) | CAS 936616-33-0 | NaV1.4 Sodium Channel Blocker (Research Use Only) | Knowlux

Product Description

Mu-Conotoxin CnIIIC (also designated XEP-018) is a synthetic 22-amino-acid conopeptide corresponding to the naturally occurring mu-conotoxin isolated from the venom of the marine cone snail Conus consors, supplied by Knowlux for laboratory research use. The peptide is constrained by three intramolecular disulfide bridges and carries a pyroglutamate at the N-terminus and an amidated C-terminus. The molecular formula is C92H139N35O28S6 and the molecular weight is 2375.7 g/mol on a free-peptide basis. Each lot is released with a lot-specific COA, MSDS and analytical traceability.

CAS and Salt Form Clarification: CAS 936616-33-0 is applied in commercial catalogues to both the free peptide and the acetate salt of Mu-Conotoxin CnIIIC. A regulatory filing for cosmetic ingredients lists the material as s-Mu-conotoxin CnIIIC acetate under this CAS, and InvivoChem catalogues an acetate form alongside the free peptide. The molecular formula C92H139N35O28S6 and molecular weight 2375.7 correspond to the free-peptide basis. If the material is supplied as the monoacetate, the molecular weight increases by approximately 60 g/mol to approximately 2435.8, and a higher acetate load shifts the mass further. Knowlux declares the salt form, acetate content, and peptide content per lot on the COA. Buyers should confirm whether the quoted material is free peptide or acetate salt before procurement, and should reconcile the molecular weight on the COA against the declared counter-ion basis rather than relying on the CAS number alone. The compound is also referred to as XEP-018, Cono Antiwrinkle, and ACETY TETRAPEPTIDE-9 in cosmetic-industry listings; these are synonyms for the same molecular entity and do not describe distinct research-grade products.

Structural Note: Mu-Conotoxin CnIIIC belongs to the mu-conotoxin family, a class of disulfide-rich peptides that block voltage-gated sodium channels at the outer pore. The peptide contains six cysteine residues forming three disulfide bonds with the connectivity Cys3-Cys15, Cys4-Cys21, and Cys10-Cys22, and the N-terminus is blocked by a pyroglutamate (Glp). This triple-disulfide architecture is essential for biological activity and distinguishes the mu-conotoxins from the omega-conotoxins, such as Ziconotide, which target presynaptic calcium channels rather than skeletal muscle sodium channels. The sequence contains no tyrosine; the aromatic residues are Trp14 and His18. It contains no methionine. The three disulfide bonds are the principal structural liability under reducing conditions, and the tryptophan is the principal oxidation liability.

Product Parameters

Product Details

1. Overview

Mu-Conotoxin CnIIIC is a 22-residue conopeptide originally isolated from the venom of Conus consors. It is a potent and persistent blocker of the skeletal muscle voltage-gated sodium channel NaV1.4, and it also blocks neuronal nicotinic acetylcholine receptors (nAChRs) as a secondary activity. The peptide produces analgesia, anaesthesia, and myorelaxation in preclinical models, and its myorelaxant properties have made it a research tool in neuromuscular pharmacology and a cosmetic ingredient candidate under the name XEP-018. The material supplied under this specification is research-grade and is not intended for human administration.

2. Receptor Pharmacology and Selectivity

Mu-Conotoxin CnIIIC binds the NaV1.4 channel with high potency and slow reversibility, a pharmacological signature that distinguishes it from rapidly reversible sodium channel blockers. InvivoChem reports an IC50 of 1.3 nM at the neuromuscular junction for the acetate form. The peptide exerts potent and preferential inhibition of NaV1.2 and NaV1.4 channels in electrophysiological studies, and it blocks neuronal nicotinic acetylcholine receptors in addition to its sodium channel activity. The dual NaV1.4/nAChR profile is a distinctive pharmacological feature of Mu-CnIIIC relative to the omega-conotoxins, which are selective for presynaptic calcium channels. The slow off-rate of Mu-CnIIIC at NaV1.4 has been documented in the primary literature and is consistent with its long-lasting myorelaxant effect. These values are assay- and system-dependent and are provided for scientific reference only.

3. Research Applications

Published pharmacological characterizations describe the following research applications:

• NaV1.4 sodium channel binding and functional blockade assays

• Neuromuscular junction transmission and myorelaxant mechanism studies

• Neuronal nicotinic acetylcholine receptor (nAChR) antagonism research

• Analgesic and anaesthetic mechanism studies in preclinical models

• Structure-activity relationship studies of mu-conotoxins (disulfide connectivity, loop length)

• Disulfide-rich peptide folding and analytical characterization

• Reference standard development for HPLC and LC-MS analytical methods

These descriptions are derived from published research and are provided for scientific reference only.

Quality Control

Solubility and Handling

Solubility: Solubility data for Mu-Conotoxin CnIIIC are inconsistent across sources in a way that warrants empirical confirmation on the specific lot. TCS Peptides describes the peptide as freely water-soluble. In direct contrast, a BrightGene product information sheet for the same CAS states that the material is virtually insoluble in glycerol and water and recommends a working pH of 4.0-8.0. ChemicalBook suppliers describe the peptide as water-soluble and recommend preparing stock solutions in sterile ultrapure water or PBS (pH 7.4) at 1-5 mg/mL. The divergence likely reflects differences in salt form (acetate versus free peptide), lot history, and whether the measurement was performed on a saturated solution with or without sonication. For practical stock preparation, water or PBS (pH 7.4) at 1-5 mg/mL is the most consistently recommended condition across suppliers, and the material should be sonicated and visually inspected before use. DMSO is not the preferred solvent for this peptide; the aqueous route is the primary option. Prepare solutions fresh and aliquot to avoid repeated freeze-thaw cycles.

Handling Precautions: Use powder-handling containment (glove box or fume hood with particulate control). Avoid inhalation of fine powder. Wear nitrile gloves, lab coat, and eye protection. The three disulfide bridges are sensitive to reducing agents; avoid contact with dithiothreitol (DTT) or mercaptoethanol. The Trp14 residue is susceptible to oxidation; protect from prolonged exposure to air and light.

Storage and Stability

Documentation Support

Per lot: COA, MSDS, HPLC chromatogram, and mass spectrometry data. Salt-form identity, acetate content, peptide content, and water content available on request. Custom specifications and third-party inspection can be arranged on a project basis.

About Knowlux

Knowlux Biotechnology is a GMP-oriented manufacturer and supplier of peptides, APIs and fine-chemical research compounds, operating from Hubei, China. We serve research groups, CDMOs and distributors in more than 40 countries, and support contract synthesis, custom packaging and technical documentation requests.

Compliance Statement

FOR RESEARCH USE ONLY. NOT FOR HUMAN USE. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE.

This product is supplied for laboratory research use only. It is not for human or animal administration, not for diagnostic or therapeutic use, not for retail sale, and not for personal use. Mu-Conotoxin CnIIIC is not approved as a medicinal product in any jurisdiction. Cosmetic-industry listings for this CAS describe anti-wrinkle or muscle-relaxant uses; those uses are outside the scope of this research-grade specification and are not endorsed by Knowlux. The purchaser is responsible for verifying product specifications against their specific research requirements and for compliance with all applicable institutional, local, and national regulations governing research chemical acquisition, storage, and use. Research context statements are for scientific reference only and do not constitute medical advice, promotional claims, or dosing guidance.

Data Verification Notes

The molecular formula C92H139N35O28S6 and molecular weight 2375.7 are confirmed by InvivoChem (COA batch V5669701), ChemicalBook, TargetMol, MedChemExpress, and Alfa Chemistry. The sequence {Glp}-GCCNGPKGCSSKWCRDHARCC-NH2 with disulfide bridges Cys3-Cys15, Cys4-Cys21, and Cys10-Cys22 is confirmed by TargetMol and MedChemExpress. The identity of CAS 936616-33-0 as Mu-Conotoxin CnIIIC (XEP-018) is confirmed across InvivoChem, TargetMol, MedChemExpress, ChemicalBook, and the UniProt entry for the Conus consors peptide. The acetate-salt format under this CAS is confirmed by a Korean cosmetic ingredient regulatory filing and by InvivoChem's acetate catalogue listing. The NaV1.4 IC50 of 1.3 nM is from InvivoChem. The dual NaV1.2/1.4 and nAChR activity is from the UniProt annotation and the primary literature cited there. Solubility values are reported with their source and conditions rather than reconciled into a single figure because the freely water-soluble and virtually insoluble in water statements are directly contradictory and likely reflect different salt forms or measurement conditions. Storage guidance is reported as specified by InvivoChem and TargetMol and is consistent across those sources.

Formatting Note: All formulas, sequences, and comparison operators use plain ASCII notation to prevent character corruption on the platform. Section headings, table alignment, and spacing follow the approved product detail pattern. No trailing spaces or non-breaking characters are used; tables use consistent pipe alignment. No web links or hyperlinks are included in this document.