Dipeptidyl peptidase-4 enzyme in diabetes mellitus

Currently, dipeptidyl peptidase-4 (DPP-4) is one of the extensively studied new targets for type-2 diabetes mellitus. Number of DPP enzymes available, such as cysteine peptidase DPP-1, serine peptidase DPP-2, metallopeptidase DPP-3, serine peptidase DPP-4, DPP-6, and DPP-10, are nonenzymatic members; cytoplasmic enzymes DPP-8,9, but only DPP-4 has proposed targeted activity. Due to its several roles in both enzymatic and nonenzymatic processes, DPP-4 is a multifaceted protein. Recent research has been focused on the strategy to preserve the endogenous glucagon-like peptide-1 activity by inhibiting the DPP-4 action because GLP and GIP have a primary role to regulate glucose levels. Compared to current conventional medications, the DPP-4 inhibitors provide improved glycaemic control over an extended period of time, are well tolerated, and are weight-neutral. DPP targets and related medications are the major topics of this chapter. Topics covered include the function of the DPP-4 enzyme in diabetes, the mode of action of DPP-4 inhibitors, the available Food and Drug Administration–approved DPP-4 inhibitors for the treatment of diabetes, and the adverse effects of DPP-4 inhibitors.