BACE1 and Alzheimer disease: AD is a devastating neurodegenerative disorder of the brain characterized by accumulation and deposition of amyloid β (Aβ) peptide, which are generated by sequential proteolytic processing of transmembrane amyloid precursor protein (APP) by two enzymes, β-secretase (β-site APP cleaving enzyme or BACE-1) and γ-secretase, in the amyloidogenic processing pathways [4,5].