Beta-Amyloid other fragments
Sequential proteolytic cleavage of the Amyloid Precursor Protein (APP) by secretases (α, β, γ) generates beta-Amyloid peptide fragments, of which beta-Amyloid 1-42 forms a major component of amyloid plaques in neurons of Alzheimer’s disease (AD) brains, while beta-Amyloid 1-40, more abundant but less toxic, is usually taken as a negative control when studying beta-Amyloid 1-42 effects in AD.
Additional minor beta-Amyloid peptides are also normally produced, such as beta-Amyloid 1-34, 1-37, 1-38 and 1-39, and few reports have quantified the levels of these peptides in the brain.
Amyloid Bri (1-23) and (1-34) peptides are post-translational products of mutated BRI2 gene. Amyloid Bri peptides are found as plaques in brains of patients with Familiar British Dementia (FBD) that shares many common features with Alzheimer’s Disease.