BACE1 and Alzheimer disease: The beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) mediates the near carboxyl terminal cleavage of the amyloid precursor protein (APP) to generate monomeric forms of the Aβ1-40/43 peptide, which aggregates to form the amyloid plaque in AD (Hampel et al, 2021).