APP and Alzheimer disease: BACE-1 (also known as ß-secretase; EC 3.4.23.46) is a membrane-associated, pepsin-like aspartic protease responsible for the cleavage of the amyloid precursor protein (APP), which gives rise to toxic ß-amyloid (Aß) peptides of various lengths, including the most pathogenic isoform, Aß42, one of the main hallmarks of Alzheimer’s disease (AD) [1].