[Asn670,Leu671]-Amyloid β//A4 Protein Precursor770 (667-675) peptide

• COA/MS/HPLC Report
• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

The peptide [Asn670,Leu671]-Amyloid //A4 Protein Precursor770 (667-675), corresponding to the sequence SEVNLDAEF, represents a variant of the wild-type β-amyloid peptide (BAP) junctional motif. This sequence incorporates a double mutation where the lysine-methionine (KM) residues at positions 670-671 of the amyloid precursor protein (APP) are replaced by asparagine-leucine (NL). In enzymatic studies, this mutant peptide is cleaved specifically at the leucine-aspartate (L/D) bond by the serine proteases cathepsin G and chymotrypsin under acidic conditions. This proteolytic event generates a fragment with an aspartate residue at its amino terminus, analogous to the cleavage observed in the wild-type motif that produces the amino terminus of BAP.

The substitution of NL for KM alters the proteolytic susceptibility of the junctional region. Unlike the wild-type peptide, cathepsins B, D, and L do not cleave this mutant sequence. The cleavage at L/D by cathepsin G and chymotrypsin suggests that these enzymes can process the mutant APP variant, potentially contributing to the generation of BAP-like fragments with a homogeneous amino-terminal aspartate. This biochemical characteristic highlights the role of specific peptide bonds and local sequence context in directing proteolytic processing within the APP molecule.

• Sahasrabudhe SR, Brown AM, Hulmes JD, Jacobsen JS, Vitek MP, Blume AJ, Sonnenberg JL. Enzymatic generation of the amino terminus of the beta-amyloid peptide. J Biol Chem. 1993 Aug 5;268(22):16699-705. PMID: 8344949.

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.