Amyloidβ is derived by the sequential cleavage of amyloid precursor protein (APP) by betaand gamma-secretases. A double missense mutation (Lys670→Asn and Met671→Leu) in APP found in a Swedish pedigree (APPβ-sw) elevates Abeta40 and Abeta42 production (1), and the mutation is utilized in establishment of transgenic mice overexpress a mutant form of human amyloid precursor protein (2). Amyloidβproduction and, beta-secretase cleavage of APP β -sw reportedly occur in the endoplasmic reticulum (ER), Golgi and endocytic compartments (3).