β- Amyloid (1-16) peptide

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

Batch to batch variation of the purity

The Amyloid (1-16) peptide is a fragment of the full-length β-amyloid peptide, encompassing its first sixteen amino acid residues. This fragment contains key histidine residues that serve as primary coordination sites for metal ions such as copper(II). Studies using potentiometric and spectroscopic methods reveal that the peptide's N-terminal amino group and imidazole nitrogens from histidine residues are involved in metal binding. The coordination mode varies with pH, forming complexes with different donor sets, including 3N and 4N coordination spheres at higher pH values.

In human and mouse variants, sequence differences influence copper(II) binding. The human Amyloid (1-16) fragment, which includes three histidine residues, can form a 3N complex involving multiple imidazole nitrogens in a wide pH range. In contrast, the mouse variant, with two histidine residues, primarily forms a 2N complex. Acetylation of the N-terminal amino group significantly alters coordination properties, shifting binding modes and complex stability. Spectroscopic data, including UV-Vis, CD, and EPR, support these coordination structures and indicate that the phenolate group of tyrosine in the human fragment does not participate in metal ion coordination.

• Kowalik-Jankowska T, Ruta M, Wiśniewska K, Lankiewicz L. Coordination abilities of the 1-16 and 1-28 fragments of beta-amyloid peptide towards copper(II) ions: a combined potentiometric and spectroscopic study. J Inorg Biochem. 2003 Jul 1;95(4):270-82. doi: 10.1016/s0162-0134(03)00128-4. PMID: 12818797.

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.