Rabbit Anti-Human APP (N-terminal) polyclonal antibody for ELISA, IHC, WB. Amyloid ? (A?) is the peptide that accumulates in the brain in Alzheimer`s disease and certain classes of cerebrovascular angiopathy. Alzheimer`s disease (AD) is characterized by the progressive formation in the brain of insoluble amyloid plaques and vascular deposits consisting of the 4-kD A?-peptide. A? generation is initiated by proteolytic cleavage of the amyloid precursor protein (APP) at the N-terminal of A? by ?-secretase. The A? peptide is then released by proteolytic cleavage at its C-terminus by g-secretase. The insoluble A? peptide forms aggregates in the vessels and senile plaques of AD brains.