Product Name | Beta-Amyloid (12-28), human |
Product Quantity | 1 mg, 97.13% Purity |
Catalog Number | L34 |
Molecular Weight | 1955.2 |
Formula | C89H135N25O25 |
Sequence | H - Val - His - His - Gln - Lys - Leu - Val - Phe - Phe - Ala - Glu - Asp - Val - Gly - Ser - Asn - Lys - OH, VHHQKLVFFAEDVGSNK, |
Product Description | Beta amyloid 1-42 is known as a biomarker of Alzheimer's disease. Amyloid is detectable in cerebrospinal fluid (CSF). It is a 42-amino acid fragment of amyloid precursor protein. The peptide is well suited for use as a standard in the quantitation of Alzheimer's. Beta amyloid (12–28) residues are the binding site for apolipoprotein E (apoE) on Beta amyloid. This sequence encompasses a hydrophobic domain (residues 14–21) and a beta-turn (residues 22–28) which place two hydrophobic domains of Beta amyloid 14 to 21 and 29 to 40/42 opposite each other, allowing for the assembly of Beta amyloid peptides into fibrils. The secondary structure of Beta amyloid (12- 28), a neutral peptide, is dominated by a-helix and random coil. The interaction of apoE with residues 12 to 28 of Beta amyloid is not just a non-specific hydrophobic interaction but plays a pivotal role in the mechanism of Aß pathology in Alzheimer’s disease (AD). Beta amyloid (11-28) and five other fragments enhanced aggregation of full length Beta amyloid (1-40). All of the peptides that enhance aggregation contained either residues 17 to 20 or 30 to 35, indicating the importance of these regions for promoting aggregation of full-length Beta amyloid. Injection of the amyloid beta-protein fragment VHHQKLVFFAEDVGSNK into different limbic system structures in mice impaired retention with remarkably similar efficacy and in a dose-dependent manner. Beta amyloid (12-28) and other Beta amyloid fragments may exert dysregulatory cognitive effects by incoordination of K? channel function in neurons, glia and endothelial cells. |
Scientific Background | Beta-Amyloid (12-28), human is a synthetic amyloid-beta (Aβ) research peptide. Amyloid-beta peptides are proteolytic products of amyloid precursor protein. Sequence length and residue composition strongly influence aggregation: Aβ42 generally aggregates more rapidly than Aβ40, and C-terminal fragments containing residues in the 34-42 region can adopt stable beta-structure. Truncated, reverse-sequence, isotopically labeled, or chemically modified Aβ constructs are therefore best interpreted as distinct research reagents rather than assumed equivalents of native Aβ40 or Aβ42. |
Research Applications | - amyloid aggregation and fibrillization studies
- LC-MS/HPLC analytical reference work
- Aβ sequence-length and modification comparisons
- antibody, binding, and assay controls
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Experimental Notes | The exact sequence, phosphorylation state, residue numbering, terminal modifications, labels, and species context should be matched to the intended assay. Sequence motifs support experimental interpretation but do not by themselves establish absolute enzyme specificity or native biological activity. |
Selected References | - Sequence determinants of enhanced amyloidogenicity of Aβ42 relative to Aβ40
- Molecular determinants of amyloid deposition: synthetic beta-protein fragments
- Impact of sequence on assembly of short amyloid peptides
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