DPP7 (dipeptidylpeptidase 7), also known as DPPII and DPP2, is a post-proline cleaving aminopeptidase expressed in quiescent lymphocytes. Dipeptidyl peptidases (DPPs) have post-proline dipeptidyl aminopeptidase activity, cleaving Xaa-Pro dipeptides from the N-termini of proteins. DPPs mediate regulatory activity of their substrates and have been linked to a variety of diseases including type 2 diabetes, obesity and cancer. DPPs can bind specific voltage-gated potassium channels and alter their expression and biophysical properties and may also influence T cells. DPP proteins include DPRP1, DPRP2, DPP3, DPP7, DPP1, DPPX and CD26. It localizes to lysosomes. DPP7 localizes to lysosomes and exists as a homodimer via its leucine zipper motif and is involved in the degradation of oligopeptides. In response to calcium release, it can be secreted in its active form. It is essential for lymphocyte survival, as the inhibition of DPP7 results in quiescent cell apoptosis.