APP and Senile plaques: The second enzyme, named β-secretase (BACE1), cuts the Aβ peptide at its N-terminal domain, generating a cell-associated amyloidogenic carboxy-terminal fragment which is processed by a third enzymatic complex enzyme called γ-secretase, which produces a soluble Aβ by cutting the APP in the middle of the neuronal membrane, generating an aggregating amyloidogenic Aβ peptide that forms the senile plaques (31).