Identification of dipeptidyl peptidase III in human neutrophils.
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.
Hashimoto
J
J
Department of Orthopaedic Surgery, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. jhashimo@rinshoken.or.jp
Yamamoto
Y
Y
Kurosawa
H
H
Nishimura
K
K
Hazato
T
T
D015081:2-Naphthylamine / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000037:antagonists & inhibitors / Q000097:blood / Q000302:isolation & purification*; D004743:Enkephalin, Leucine / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D009504:Neutrophils / Q000201:enzymology*; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity
D009842:Oligopeptides; D010446:Peptide Fragments; D011480:Protease Inhibitors; C082392:spinorphin; D004743:Enkephalin, Leucine; D015081:2-Naphthylamine; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C100152:dipeptidyl peptidase III