Dipeptidyl peptidase-4 (DPP4 orDPPIV), also known asadenosine deaminase complexing protein 2 orCD26 (cluster of differentiation 26) is aprotein that, in humans, is encoded by theDPP4gene.[5] DPP4 is related toFAP,DPP8, andDPP9. The enzyme was discovered in 1966 by Hopsu-Havu and Glenner,[6] and as a result of various studies on chemism, was called dipeptidyl peptidase IV [DP IV].
The protein encoded by theDPP4 gene is anenzyme expressed on the surface of most cell types and is associated with immune regulation,signal transduction, andapoptosis. It is a type II transmembraneglycoprotein, but a soluble form, which lacks the intracellular and transmembrane part, is present in blood plasma and various body fluids. DPP-4 is aserineexopeptidase that cleaves X-proline or X-alaninedipeptides from theN-terminus ofpolypeptides. Peptide bonds involving the cyclic amino acid proline cannot be cleaved by the majority of proteases and an N-terminal X-proline "shields" various biopeptides.[7] Extracellular proline-specific proteases therefore play an important role in the regulation of these biopeptides.
DPP-4 is known to cleave a broad range ofsubstrates includinggrowth factors,chemokines,neuropeptides, andvasoactive peptides.[8][9] The cleaved substrates lose their biological activity in the majority of cases, but in the case of the chemokineRANTES andneuropeptide Y, DPP-4 mediated cleavage leads to a shift in the receptor subtype binding.[8]
DPP4 plays a major role inglucose metabolism. It is responsible for the degradation ofincretins such asGLP-1.[10] Furthermore, it appears to work as a suppressor in the development of sometumors.[11][12][13][14]
DPP-4 also binds the enzymeadenosine deaminase specifically and with high affinity. The significance of this interaction has yet to be established.
CD26/DPPIV plays an important role in tumor biology, and is useful as a marker for various cancers, with its levels either on the cell surface or in the serum increased in someneoplasms and decreased in others.[17]
Middle East respiratory syndrome coronavirus has been found to bind to DPP4. It is found on the surface of cells in the airways (such as the lungs) and kidneys. Scientists may be able to use this to their advantage by blocking the virus's entry into the cell.[19]
DPP4,[20] or its Mycobacterial homologue MtDPP,[21] might play a role in the pathogenesis oftuberculosis via cleavage of thechemokine C-X-C motif chemokine ligand 10 (CXCL10).
^Chen X (2006). "Biochemical properties of recombinant prolyl dipeptidases DPP-IV and DPP8".Dipeptidyl Aminopeptidases. Advances in Experimental Medicine and Biology. Vol. 575. pp. 27–32.doi:10.1007/0-387-32824-6_3.ISBN978-0-387-29058-4.PMID16700505.
^Pro B, Dang NH (October 2004). "CD26/dipeptidyl peptidase IV and its role in cancer".Histology and Histopathology.19 (4):1345–51.doi:10.14670/HH-19.1345.PMID15375776.
^Wesley UV, McGroarty M, Homoyouni A (February 2005). "Dipeptidyl peptidase inhibits malignant phenotype of prostate cancer cells by blocking basic fibroblast growth factor signaling pathway".Cancer Research.65 (4):1325–34.doi:10.1158/0008-5472.CAN-04-1852.PMID15735018.
^Busek P, Malík R, Sedo A (March 2004). "Dipeptidyl peptidase IV activity and/or structure homologues (DASH) and their substrates in cancer".The International Journal of Biochemistry & Cell Biology.36 (3):408–21.doi:10.1016/S1357-2725(03)00262-0.PMID14687920.
^Kaji K, Yoshiji H, Ikenaka Y, Noguchi R, Aihara Y, Douhara A, Moriya K, Kawaratani H, Shirai Y, Yoshii J, Yanase K, Kitade M, Namisaki T, Fukui H (March 2014). "Dipeptidyl peptidase-4 inhibitor attenuates hepatic fibrosis via suppression of activated hepatic stellate cell in rats".Journal of Gastroenterology.49 (3):481–91.doi:10.1007/s00535-013-0783-4.PMID23475323.S2CID2726091.
^Rosenstock J, Zinman B (April 2007). "Dipeptidyl peptidase-4 inhibitors and the management of type 2 diabetes mellitus".Current Opinion in Endocrinology, Diabetes and Obesity.14 (2):98–107.doi:10.1097/MED.0b013e3280a02f65.PMID17940427.S2CID25482131.
Ansorge S, Bühling F, Kähne T, Lendeckel U, Reinhold D, Täger M, Wrenger S (1997). "CD26/Dipeptidyl Peptidase IV in Lymphocyte Growth Regulation".Cellular Peptidases in Immune Functions and Diseases. Advances in Experimental Medicine and Biology. Vol. 421. pp. 127–40.doi:10.1007/978-1-4757-9613-1_17.ISBN978-1-4757-9615-5.PMID9330689.
Reinhold D, Kähne T, Steinbrecher A, Wrenger S, Neubert K, Ansorge S, Brocke S (2003). "The role of dipeptidyl peptidase IV (DP IV) enzymatic activity in T cell activation and autoimmunity".Biological Chemistry.383 (7–8):1133–8.doi:10.1515/BC.2002.123.PMID12437097.S2CID30027839.
Sato K, Dang NH (March 2003). "CD26: a novel treatment target for T-cell lymphoid malignancies? (Review)".International Journal of Oncology.22 (3):481–97.doi:10.3892/ijo.22.3.481 (inactive 12 July 2025).PMID12579300.{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link)
de Meester I, Lambeir AM, Proost P, Scharpé S (2003). "Dipeptidyl Peptidase IV Substrates".Dipeptidyl Aminopeptidases in Health and Disease. Advances in Experimental Medicine and Biology. Vol. 524. pp. 3–17.doi:10.1007/0-306-47920-6_1.ISBN0-306-47717-3.PMID12675218.
Koch S, Anthonsen D, Skovbjerg H, Sjöström H (2003). "On the role of dipeptidyl peptidase IV in the digestion of an immunodominant epitope in celiac disease".Dipeptidyl Aminopeptidases in Health and Disease. Advances in Experimental Medicine and Biology. Vol. 524. pp. 181–7.doi:10.1007/0-306-47920-6_22.ISBN0-306-47717-3.PMID12675238.
Pro B, Dang NH (October 2004). "CD26/dipeptidyl peptidase IV and its role in cancer".Histology and Histopathology.19 (4):1345–51.doi:10.14670/HH-19.1345.PMID15375776.