Solnatide (AP301) peptide

• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

Solnatide (AP301) is a cyclic peptide with the sequence Cyclo(CGQRETPEGAEAKPWYC), derived from the lectin-like domain (TIP domain) of human tumor necrosis factor. This peptide functions as an activator of the epithelial sodium channel (ENaC), a key ion channel involved in sodium transport across epithelial tissues. Mechanistic studies in heterologous expression systems, including human embryonic kidney and Chinese hamster ovary cells, demonstrate that AP301 specifically enhances amiloride-sensitive sodium currents through ENaC. The peptide increases channel activity by elevating single-channel open probability, without altering single-channel conductance, and this activation occurs in a reversible manner.

The activity of AP301 is dependent on the post-translational state of ENaC. It activates proteolytically cleaved channels but shows no effect on near-silent, uncleaved channels. Maximal activation requires coexpression of pore-forming subunits (α or δ) alongside β and γ subunits. Additionally, the interaction between AP301 and ENaC is critically dependent on the glycosylation of extracellular loop domains, as deglycosylation abolishes its activating effect. This requirement for glycosylated extracellular regions indicates that AP301 binds to specific carbohydrate moieties on the channel, which are essential for its modulatory action.

• Shabbir W, Scherbaum-Hazemi P, Tzotzos S, et al. Mechanism of action of novel lung edema therapeutic AP301 by activation of the epithelial sodium channel. Molecular Pharmacology. 2013 Dec;84(6):899-910. DOI: 10.1124/mol.113.089409. PMID: 24077967; PMCID: PMC3834145.

Trifluoroacetic acid (TFA) is a common counterion from the purification process using High-Performance Liquid Chromatography (HPLC). The presence of TFA can affect the peptide's net weight, appearance, and solubility.

Impact on Net Weight: The TFA salt contributes to the total mass of the product. In most cases, the peptide content constitutes >80% of the total weight, with TFA accounting for the remainder.

Solubility: TFA salts generally enhance the solubility of peptides in aqueous solutions.

In Biological Assays: For most standard in vitro assays, the residual TFA levels do not cause interference. However, for highly sensitive cellular or biochemical studies, please be aware of its presence.