β-Amyloid (12-28) peptide

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

Batch to batch variation of the purity

The β-Amyloid (12-28) peptide is a fragment of the full-length β-amyloid protein. This peptide encompasses residues 12 to 28 of the native sequence and contains a central hydrophobic region. Studies using techniques such as pulsed-field gradient NMR spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy have shown that the β-Amyloid (12-28) fragment undergoes a time-dependent aggregation process. The soluble fraction initially consists of monomeric species, which form oligomeric intermediates over time. These intermediates adopt an extended, non-spherical assembly. The aggregation ultimately results in the formation of fibrillar structures.

These fibrillar aggregates exhibit a characteristic antiparallel β-sheet secondary structure, as confirmed by infrared spectroscopy. The aggregation kinetics of the β-Amyloid (12-28) fragment are noted to be slower compared to the full-length protein, but the resulting fibrillar morphology is similar. The peptide's behavior in solution, particularly the early oligomerization stages observed via NMR diffusion measurements, makes it a frequently studied model for investigating the fundamental biophysical processes of amyloid formation.

• Rabanal F, Tusell JM, Sastre L, Quintero MR, Cruz M, Grillo D, Pons M, Albericio F, Serratosa J, Giralt E. Structural, kinetic and cytotoxicity aspects of 12-28 beta-amyloid protein fragment: a reappraisal. J Pept Sci. 2002 Oct;8(10):578-88. doi: 10.1002/psc.418. PMID: 12450327.

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.