β-Amyloid (1-42), human

This peptide is well suited to the quantitative determination of A 42 peptide. Alzheimer’s disease (AD) is characterized by the presence of extracellular plaques and intracellular neurofibrillary tangles (NFTs) in the brain. The major protein component of these plaques is beta amyloid peptide (A), a 40- to 43- amino-acid peptide cleaved from amyloid precursor protein by secretase (BACE) and a putative (gamma) secretase. Increased release of the ‘longer forms’ of A peptide, A 42 and A 43, which have a greater tendency to aggregate than A 40, occurs in individuals expressing certain genetic mutations, expressing certain ApoE alleles or may other, still undiscovered factors.