Linaclotide | CAS 851199-59-2 | Guanylate Cyclase-C Agonist (Research Use Only) | Knowlux

Product Description

Linaclotide, CAS 851199-59-2, is a synthetic 14-amino-acid peptide agonist of guanylate cyclase-C (GC-C), supplied by Knowlux for laboratory research use. The peptide is constrained by three intramolecular disulfide bridges, yielding a compact, heavily cross-linked structure. The molecular formula is C59H79N15O21S6 and the molecular weight is 1526.74 g/mol. Each lot is released with a lot-specific COA, MSDS and analytical traceability.

CAS and Salt Form Clarification: CAS 851199-59-2 is the registry for the Linaclotide free base. The acetate salt form is assigned CAS 851199-60-5 and is frequently conflated with the free base in supplier listings. Knowlux declares the salt basis and counter-ion content per lot on the COA. Buyers should confirm whether the quoted material is free base or acetate salt before procurement, as the counter-ion affects mass balance and apparent potency in formulation studies.

Structural Complexity Note: Linaclotide contains six cysteine residues forming three disulfide bonds (Cys1-Cys6, Cys2-Cys10, Cys5-Cys13). This level of oxidative folding makes correct disulfide connectivity a critical quality attribute. Buyers should request confirmation that the COA includes disulfide mapping or enzymatic digest data, not only a single HPLC purity figure.

Product Parameters

Product Details

1. Overview

Linaclotide is a 14-residue synthetic peptide that functions as a potent and selective agonist of guanylate cyclase-C (GC-C), a receptor expressed on the apical surface of intestinal enterocytes. Activation of GC-C elevates intracellular cyclic GMP, which in turn drives chloride and bicarbonate secretion through the CFTR channel and accelerates gastrointestinal transit. In clinical medicine, linaclotide is approved for constipation-predominant irritable bowel syndrome (IBS-C) and chronic idiopathic constipation (CIC). The material supplied under this specification is research-grade and is not intended for human administration. Knowlux supplies this compound strictly for laboratory investigation of GC-C signaling, intestinal ion transport, and peptide stability.

2. Structural Profile

The linear sequence is H-Cys-Cys-Glu-Tyr-Cys-Cys-Asn-Pro-Ala-Cys-Thr-Gly-Cys-Tyr-OH, with three disulfide bonds linking Cys1 to Cys6, Cys2 to Cys10, and Cys5 to Cys13. This tri-cyclic architecture confers remarkable resistance to proteolytic degradation in the gastrointestinal lumen, a property that underpins the peptide's ability to act locally at the GC-C receptor without systemic absorption. The free N-terminus and free C-terminal carboxylate distinguish linaclotide from terminally blocked research peptides in the Semax and Melanotan families. The unusually high cysteine content (6 of 14 residues) also makes the molecule sensitive to reducing agents and to non-specific disulfide scrambling under denaturing conditions.

3. Research Applications

Published pharmacological characterizations describe the following research applications:

• GC-C receptor binding and cGMP accumulation assays in intestinal cell models

• Intestinal ion transport and fluid secretion studies

• Peptide folding and disulfide connectivity analysis (a model system for polycyclic peptide characterization)

• Analytical method development for complex, multi-disulfide peptides

• Gastrointestinal motility and visceral hypersensitivity research models

These descriptions are derived from published research and are provided for scientific reference only. They do not constitute clinical guidance or dosing recommendations.

Quality Control

Solubility and Handling

Solubility: Linaclotide solubility is pH- and matrix-dependent, and supplier data vary accordingly. In DMSO, reported solubility ranges from approximately 30 mg/mL to <50 mg/mL depending on the lot and grade. Aqueous solubility is more constrained: one supplier reports water solubility of approximately 9 mg/mL after adjusting to pH 2 with HCl, while others describe the compound as very slightly soluble in water or as requiring sonication and warming. For aqueous buffers near neutral pH, solubility may be substantially lower than acidic conditions. Prepare solutions fresh and aliquot to avoid repeated freeze-thaw cycles; do not assume a single reported solubility value will apply across buffer systems.

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 bonds are vulnerable to reduction and to exchange with free thiols; avoid contact with dithiothreitol (DTT), mercaptoethanol, or other reducing agents, and avoid prolonged exposure to denaturing conditions that can promote disulfide scrambling.

Storage and Stability

Storage guidance varies among suppliers: one lists 1 year at -20C for powder, another specifies 3 years at -20C for powder, and a third recommends 4C for short-term storage. Linaclotide is hygroscopic and should be equilibrated to room temperature before opening to prevent condensation. Protect from light.

Documentation Support

Per lot: COA, MSDS, certificate of origin, HPLC chromatogram, and mass spectrometry data. Disulfide mapping or digest data available on request for activity-sensitive applications. 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. Linaclotide is an approved medicinal product in certain jurisdictions for specific clinical indications; however, the material offered under this specification is research-grade and is not intended for clinical use. 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.