The Neprilysin family includes Neprilysin, Neprilysin-2, ECE-2, PEX, DINE, Kell and several NEP-like proteins. Neprilysin (NEP) is a cell surface zinc protease expressed by a variety of cells. NEP is able to cleave brain enkephalins, inactivate circulating atrial natriuretic peptide, and degrade amyloid beta peptide (Abeta). Neprilysin-2 exists in both type II transmembrane and soluble forms and is highly expressed in the testes.