Dipeptidyl-Peptidases (DPPs) and Tripeptidyl-Peptidases (TPPs) are types of enzymes that break down peptides, which are chains of amino acids. DPPs cleave dipeptides, which are two amino acids, from the N-terminus (the end with a free amino group) of a peptide or protein. TPPs, on the other hand, cleave tripeptides, which are three amino acids, from the N-terminus of a peptide or protein. These enzymes play important roles in regulating various physiological processes, including digestion, immune function, and blood sugar control. Inhibition of certain DPPs (such as DPP-4) has been shown to be beneficial in the treatment of type 2 diabetes, as it increases the levels of incretin hormones which promote insulin secretion and decrease glucagon secretion.