Identification of dipeptidyl peptidase III in human neutrophils

Biochem Biophys Res Commun. 2000 Jul 5;273(2):393-7. doi: 10.1006/bbrc.2000.2827.

Abstract

We have found activity of dipeptidyl peptidase (DPP) III, one of the most important enkephalin-degrading enzymes in the central nervous system, in human neutrophils. HPLC analysis of the peptide fragments produced by treatment of leucine-enkephalin with isolated neutrophils in the presence of inhibitors of other enkephalin-degrading enzymes revealed that the enzyme in human neutrophils cleaved dipeptides from the NH(2) terminus of leucine-enkephalin, suggesting the presence of DPPIII activity in human neutrophils. Using a specific synthesized substrate and proteinase inhibitors, it was found that the neutrophils have 19.2 +/- 3.6 microM/h/5 x 10(6) cells of beta-naphthylamine for the enzyme. It was also confirmed that spinorphin and tynorphin, both reported to inhibit the activities of enkephalin-degrading enzymes, had potent inhibitory activities (IC(50): 4.0 and 0.029 microg/ml, respectively) against the enzyme. The presence of DPPIII activity in human neutrophils suggests that the biologically active peptides which are associated with enkephalin play a physiological role in regulating enkephalin or inflammatory mechanisms in peripheral tissues.

MeSH terms

  • 2-Naphthylamine / metabolism
  • Animals
  • Chromatography, High Pressure Liquid
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / antagonists & inhibitors
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / blood
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / isolation & purification*
  • Enkephalin, Leucine / metabolism
  • Humans
  • In Vitro Techniques
  • Neutrophils / enzymology*
  • Oligopeptides / pharmacology
  • Peptide Fragments / metabolism
  • Protease Inhibitors / pharmacology
  • Substrate Specificity

Substances

  • Oligopeptides
  • Peptide Fragments
  • Protease Inhibitors
  • spinorphin
  • Enkephalin, Leucine
  • 2-Naphthylamine
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases
  • dipeptidyl peptidase III