Cathepsin D is an endosomal-lysosomal aspartic protease implicated in breast cancer metastasis and Alzheimer’s disease. Lysosomal release of cathepsin D has been found to precede cytochrome c release and loss of membrane potential in apoptotic human foreskin fibroblasts. Cathepsin D levels in PC12 cells increase 12 to 24 hours after apoptosis is induced.http://www.creative-enzymes.com/product/Native-Human-Cathepsin-D_981.html