Amyloid beta denotes peptides of 36–43 amino acids that are crucially involved in Alzheimer's diseaseas the main component of the amyloid plaques found in the brains of Alzheimer patients. The peptides derive from theamyloid precursor protein (APP), which is cleaved by beta secretase and gamma secretase to yield Aβ. Aβ molecules can aggregate to form flexible soluble oligomers which may exist in several forms.