Beta-Secretase (beta-SEC) is responsible for the intramembrane cleavage of amyloid precursor protein, an event intimately linked to Alzheimer's disease (AD). Beta-SEC is an aspartic protease composed by presenilin, nicastrin (NCT), APH-1, and PEN-2.Beta-SEC appears to have a very broad specificity; however, no quantitative data is available to support this assumption. NCT subunit is a type 1 membr ...