Dipeptidyl peptidase-4 (DPP4orDPPIV), also known as adenosine deaminase complexing protein 2orCD26 (cluster of differentiation26) is a protein that, in humans, is encoded by the DPP4 gene.[5] DPP4 is related to FAP, DPP8, and DPP9. 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 the DPP4 gene is an enzyme expressed on the surface of most cell types and is associated with immune regulation, signal transduction, and apoptosis. It is a type II transmembrane glycoprotein, but a soluble form, which lacks the intracellular and transmembrane part, is present in blood plasma and various body fluids. DPP-4 is a serine exopeptidase that cleaves X-proline or X-alanine dipeptides from the N-terminusofpolypeptides. 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 of substrates including growth factors, chemokines, neuropeptides, and vasoactive peptides.[8][9] The cleaved substrates lose their biological activity in the majority of cases, but in the case of the chemokine RANTES and neuropeptide Y, DPP-4 mediated cleavage leads to a shift in the receptor subtype binding.[8]
DPP4 plays a major role in glucose metabolism. It is responsible for the degradation of incretins such as GLP-1.[10] Furthermore, it appears to work as a suppressor in the development of some tumors.[11][12][13][14]
DPP-4 also binds the enzyme adenosine deaminase specifically and with high affinity. The significance of this interaction has yet to be established.
Animal studies suggest its pathogenetic role in development of fibrosis of various organs, such as liver and kidney.[15][16]
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 some neoplasms and decreased in others.[17]
A class of oral hypoglycemics called dipeptidyl peptidase-4 inhibitors works by inhibiting the action of this enzyme, thereby prolonging incretin effect in vivo.[18]
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 of tuberculosis via cleavage of the chemokine C-X-C motif chemokine ligand 10 (CXCL10).
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PDB gallery
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1j2e: Crystal structure of Human Dipeptidyl peptidase IV
1n1m: Human Dipeptidyl Peptidase IV/CD26 in complex with an inhibitor
1nu6: Crystal structure of human Dipeptidyl Peptidase IV (DPP-IV)
1nu8: Crystal structure of human dipeptidyl peptidase IV (DPP-IV) in complex with Diprotin A (ILI)
1pfq: crystal structure of human apo dipeptidyl peptidase IV / CD26
1r9m: Crystal Structure of Human Dipeptidyl Peptidase IV at 2.1 Ang. Resolution.
1r9n: Crystal Structure of human dipeptidyl peptidase IV in complex with a decapeptide (tNPY) at 2.3 Ang. Resolution
1rwq: Human Dipeptidyl peptidase IV in complex with 5-aminomethyl-6-(2,4-dichloro-phenyl)-2-(3,5-dimethoxy-phenyl)-pyrimidin-4-ylamine
1tk3: Crystal Structure Of Human Apo Dipeptidyl Peptidase IV/CD26
1tkr: Human Dipeptidyl Peptidase IV/CD26 inhibited with Diisopropyl FluoroPhosphate
1u8e: HUMAN DIPEPTIDYL PEPTIDASE IV/CD26 MUTANT Y547F
1w1i: CRYSTAL STRUCTURE OF DIPEPTIDYL PEPTIDASE IV (DPPIV OR CD26) IN COMPLEX WITH ADENOSINE DEAMINASE
1wcy: Crystal Structure Of Human Dipeptidyl Peptidase IV (DPPIV) Complex With Diprotin A
1x70: HUMAN DIPEPTIDYL PEPTIDASE IV IN COMPLEX WITH A BETA AMINO ACID INHIBITOR
2ajl: X-ray Structure of Novel Biaryl-Based Dipeptidyl peptidase IV inhibitor
2bgn: HIV-1 TAT PROTEIN DERIVED N-TERMINAL NONAPEPTIDE TRP2-TAT (1-9) BOUND TO THE ACTIVE SITE OF DIPEPTIDYL PEPTIDASE IV (CD26)
2bgr: CRYSTAL STRUCTURE OF HIV-1 TAT DERIVED NONAPEPTIDES TAT(1-9) BOUND TO THE ACTIVE SITE OF DIPEPTIDYL PEPTIDASE IV (CD26)
2bub: CRYSTAL STRUCTURE OF HUMAN DIPEPTIDYL PEPTIDASE IV (CD26) IN COMPLEX WITH A REVERSED AMIDE INHIBITOR
2fjp: Human dipeptidyl peptidase IV/CD26 in complex with an inhibitor
2g5p: Crystal structure of human dipeptidyl peptidase IV (DPPIV) complexed with cyanopyrrolidine (C5-pro-pro) inhibitor 21ac
2g5t: Crystal structure of human dipeptidyl peptidase IV (DPPIV) complexed with cyanopyrrolidine (C5-pro-pro) inhibitor 21ag
2g63: Crystal structure of human dipeptidyl peptidase IV (DPPIV) complexed with cyanopyrrolidine (C5-pro-pro) inhibitor 24b
2hha: The structure of DPP4 in complex with an oxadiazole inhibitor
2i03: Crystal structure of human dipeptidyl peptidase 4 (DPP IV) with potent alkynyl cyanopyrrolidine (ABT-279)
2iit: Human dipeptidyl peptidase 4 in complex with a diazepan-2-one inhibitor
2iiv: Human dipeptidyl peptidase 4 in complex with a diazepan-2-one inhibitor
2ogz: Crystal structure of DPP-IV complexed with Lilly aryl ketone inhibitor
2oph: Human dipeptidyl peptidase IV in complex with an alpha amino acid inhibitor
2oqi: Human Dipeptidyl Peptidase IV (DPP4) with Piperidinone-constrained phenethylamine
2oqv: Human Dipeptidyl Peptidase IV (DPP4) with piperidine-constrained phenethylamine
2p8s: Human dipeptidyl peptidase IV/CD26 in complex with a cyclohexalamine inhibitor
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Cluster of differentiation by lineage
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3.4.11-19: Exopeptidase |
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3.4.21-25: Endopeptidase |
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3.4.99: Unknown |
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