Dipeptidase 1 (DPEP1) is a kidney membrane enzyme that belongs to the peptidase M19 family. DPEP1 is a homodimer and is inhibited by L-penicillamine. DPEP1 hydrolyzes a variety of dipeptides and is implicated in renal metabolism of glutathione and its conjugates. DPEP1 is responsible for hydrolysis of the beta-lactam ring of antibiotics; such as penem and carbapenem. DPEP1 may play an important role in the regulation of leukotriene activity. DPEP1 expression in cancer is significantly higher than that in normal tissue. However; DPEP1 expression decreased with pathological differentiation; lymph-node and distant metastasis.