β-Amyloid (31-35) peptide

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

Batch to batch variation of the purity

The amyloid beta-peptide (AbP) fragment 31–35 [AbP(31–35)] is a pentapeptide derived from the full-length amyloid beta-protein. This fragment contains the methionine-35 (Met-35) residue, which is critical for its biological activity. Studies indicate that AbP(31–35) exhibits neurotoxic properties in neuronal cell models, such as rat cerebellar granule cells. The redox state of the Met-35 residue significantly influences its effects; the peptide with reduced Met-35 induces a more potent decrease in cell viability compared to its oxidized counterpart.

The mechanism of action involves the induction of apoptotic pathways. AbP(31–35) with reduced Met-35 triggers an early and selective increase in the mRNA levels of the pro-apoptotic gene bax. This upregulation is followed by a delayed activation of the executioner caspase-3 enzyme. In contrast, the oxidized form of the peptide causes a smaller and slower increase in bax expression and caspase-3 activity. Substitution of Met-35 with norleucine completely abolishes these toxic effects, underscoring the essential role of this specific amino acid in the peptide's function.

• Misiti F, Clementi ME, Tringali G, Vairano M, Orsini F, Pezzotti M, Navarra P, Giardina B, Pozzoli G. Fragment 31-35 of beta-amyloid peptide induces neurodegeneration in rat cerebellar granule cells via bax gene expression and caspase-3 activation. A crucial role for the redox state of methionine-35 residue. Neurochem Int. 2006 Oct;49(5):525-32. doi: 10.1016/j.neuint.2006.03.014. Epub 2006 May 23. PMID: 16720060.

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.