The proteolytic degradation of Aβ is a major route of clearance and plays an important role in the pathology of Alzheimer’s Disease (AD). A variety of Aβ degrading enzymes have been found. Of these enzymes, neprilysin (NEP or CD10 or common acute lymphoblastic leukemia antigen (CALLA); EC 3.4.24.11) is considered one of the most important for the control of cerebral Aβ levels. Neprilysins (NEPs, neutral endopeptidases) and the neprilysin-like peptidases are typically type II integral membrane proteins with their active sites facing the extracellular environment[1]. They are members of the family of zinc-metalloproteases and have been known to play a central role in the regulatory processes of cell-cell signalling. Being thermolysin-like metalloendopeptidases, the family of NEPs comprise angiotensin-converting enzymes (ACE), endothelin-converting enzymes (ECE) and thimet oligopeptidases (TOP)[2].