Platelets and Alzheimer’s disease: Potential of APP as a biomarker

Figure 2 Proteolytic processing of amyloid precursor protein by the secretases. In a non-amyloidogenic pathway, α-secretase cleaves amyloid precursor protein (APP) within the Aβ domain to release the α-cleaved soluble N-terminal fragment, sAPPα. β-Amyloid precursor cleaving enzyme (BACE) cleaves APP at the N-terminus of Aβ to release the β-cleaved soluble N-terminal fragment sAPPβ, and thereby initiates the amyloidogenic pathway. The remaining 99 amino acid-long C-terminal fragment (C99) is further processed at multiple sites by γ-secretase to release the APP intracellular domain (AICD) in the cytosol and Aβ peptides in the extracellular space.