Cathepsin D (active, human)

Cathepsin D is an estrogen-regulated protein associated with tissue breakdown. Levels of cathepsin D have been positively correlated with recurring breast cancers of both node negative and node positive types. Additionally cathepsin D has been associated with amyloid formation in Alzheimer’s plaques. As cathepsin D activity is increased by cigarette smoke, the enzyme may contribute to lung tissue damage in smokers.