Dipeptidyl peptidase III (DPPIII), the sole member of the M49 family of metalloproteases, is a zinc-dependent aminopeptidase that specifically cleaves dipeptides at the N-terminus. DPPIII is mainly found as a cytosolic protein although some studies suggest a potential localization in membranes. DPPIII is associated with important physiological functions in mammals and it is widely distributed in several tissues such as brain, liver, kidney, pancreas, spleen and lungs. A variety of small peptides such as Met-enkephalin and angiotensin I and II are targets of the enzyme, however the full range of substrate peptides remains undefined.