CTAP peptide

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

Batch to batch variation of the purity

CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr) is a highly selective μ-opioid receptor antagonist with an IC₅₀ of 3.5 nM and over 1200-fold selectivity for μ-opioid receptors compared to δ-opioid receptors. This cyclic peptide exhibits blood-brain barrier permeability, enabling in vivo activity upon systemic administration. A glycosylated derivative, gCTAP5, was developed to enhance stability by incorporating a β-glucopyranoside moiety at the C-terminus. Both compounds demonstrate potent μ-opioid receptor antagonism, as evidenced by their ability to block morphine-induced antinociception in rodent models.

Structurally, CTAP belongs to the class of constrained cyclic peptides, featuring a disulfide bridge between cysteine and penicillamine residues. The glycosylation in gCTAP5 involves a serine-linked β-glucopyranoside appended via a glycine-glycine spacer. Synthetic preparation employs solid-phase Fmoc chemistry, followed by oxidative cyclization and purification via reverse-phase HPLC. These peptides serve as valuable tools for investigating μ-opioid receptor-specific signaling in neurological contexts.

• Bartlett MJ, So LY, Szabò L, Skinner DP, Parent KL, Heien ML, Vanderah TW, Polt R, Sherman SJ, Falk T. Highly-selective µ-opioid receptor antagonism does not block L-DOPA-induced dyskinesia in a rodent model. BMC Res Notes. 2020 Mar 12;13(1):149. doi: 10.1186/s13104-020-04994-7. PMID: 32164786; PMCID: PMC7066739.

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.