Citrullinated amyloid-β (1-40) peptide (human) (Citrullinated Aβ (1-40)) is a modified form of β-Amyloid (1-40) with a citrullination at the Arg5 site. Citrullinated amyloid-β (1-40) peptide (human) exhibits increased transient formation of soluble oligomers and insoluble aggregates composed of distorted parallel β-sheets compared with unmodified β-Amyloid (1-40).