Prolyl peptidases related to dipeptidyl peptidase IV: potential of specific inhibitors in drug discovery.

Dipeptidyl peptidase IV (DPP IV) is a validated target for the treatment of type 2 diabetes, with several inhibitors currently in phase 3 clinical trials. This review will mainly focus on proline-specific dipeptidyl peptidases related to DPP IV: fibroblast activation protein (FAP), dipeptidyl peptidase 8 (DPP8), dipeptidyl peptidase 9 (DPP9) and dipeptidyl peptidase II (DPP II). The biochemical and biological properties of these enzymes will be discussed, as well as the therapeutic potential of their inhibition. The development of potent and selective inhibitors for each of these peptidases will be described.