Proteolytic processing of neuropeptide Y and peptide YY by dipeptidyl peptidase IV

Regul Pept. 1993 Dec 10;49(2):133-44. doi: 10.1016/0167-0115(93)90435-b.


Neuropeptide Y, peptide YY and pancreatic polypeptide share an evolutionary conserved proline-rich N-terminal sequence, a structure generally known to be inert to the attack of common proteinases, but a potential target for specialized proline-specific aminopeptidases. Purified human dipeptidyl peptidase IV (also termed CD 26) liberated N-terminal Tyr-Pro from both, neuropeptide Y and peptide YY, with very high specific activities and Km values in the micromolar range, but almost no Ala-Pro from pancreatic polypeptide. Other proline-specific aminopeptidases exhibited low (aminopeptidase P, liberation of N-terminal Tyr) or totally no activity (dipeptidyl peptidase II), as was also observed with less-specific aminopeptidases (aminopeptidase M, leucine aminopeptidase). When human serum was incubated with neuropeptide Y or peptide YY at micro- and nanomolar concentrations, Tyr-Pro was detected as a metabolite of both peptides. Formation of Tyr-Pro in serum was blocked in the presence of Lys-pyrrolidine and diprotin A (Ile-Pro-Ile), specific, competitive inhibitors of dipeptidyl peptidase IV. Incubation of neuropeptide Y or peptide YY with immunocytochemically defined, cultivated endothelial cells from human umbilical cord also yielded Tyr-Pro. Dipeptidyl peptidase IV could be immunostained on most endothelial cells by a specific antibody. We suggest that dipeptidyl peptidase IV might be involved in the degradation of neuropeptide Y and peptide YY to N-terminal truncated neuropeptide Y(3-36) and peptide YY(3-36). Since specific binding to Y1, but not to Y2 subtype of neuropeptide Y/peptide YY receptors requires intact N- as well as C-termini of neuropeptide Y and peptide YY, removal of their amino-terminal dipeptides by dipeptidyl peptidase IV inactivates them for binding to one receptor subtype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cells, Cultured
  • Dipeptidyl Peptidase 4
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / metabolism*
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / metabolism
  • Humans
  • Molecular Sequence Data
  • Neuropeptide Y / blood
  • Neuropeptide Y / metabolism*
  • Peptide YY
  • Peptides / blood
  • Peptides / metabolism*
  • Protein Processing, Post-Translational*
  • Sequence Homology, Amino Acid


  • Neuropeptide Y
  • Peptides
  • Peptide YY
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases
  • Dipeptidyl Peptidase 4