Insulysin, or insulin-degrading enzyme (IDE), is a zinc metallopeptidase of the inverzincin family. IDE is primarily located in the cytosol, but has been detected as a secreted enzyme and associated with the plasma membrane as well. The enzyme is expressed in many tissues, with the highest levels in liver, kidney, brain, and testis. IDE hydrolyzes a variety of regulatory peptides, including insulin, glucagon, atrial natriuretic factor, and transforming growth factor-alpha
in vitro. In addition, IDE has been shown to degrade the amyloid beta (A beta) peptide, which polymerizes into the plaques associated with Alzheimer's disease.