Description_x000D_ Amino Acid Sequence_x000D_ Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-Leu-Val-Phe-Phe-Ala-Gly-Asp-Val-Gly-Ser-Asn-Lys-Gly-Ala-Ile-Ile-Gly-Leu-Met-Val-Gly-Gly-Val-Val_x000D_ General description_x000D_ β-Amyloid peptides are the major constituents of senile plaques and neurofibrillary tangles that occur in the hippocampus, neocortex, and amygdala of patients with Alzheimer′s disease. Aβ (1-40) whether soluble or insoluble differentiates AD vs high pathology controls. The Arctic mutation E22G causes early onset of Alzheimer′s compared to wild type and promotes protofibril formation and neurotoxicity.