– (Glu20)-Amyloid β-Protein (1-42) represents a variant of amyloid β-protein (Aβ) that fibrillizes more slowly due to the Glu20 mutation, which diminishes Aβ42’s tendency to aggregate and inhibits the accumulation of this slowly fibrillizing peptide. Amyloid β-protein is the principal constituent of amyloid deposits in the vascular system and brain parenchyma in Alzheimer’s disease [1] [2].