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Corpus Systématique Animale

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Dipeptidyl peptidase IV in mammalian lungs

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Springer (journals)
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Mots-clés d'auteur
  • Dipeptidyl peptidase IV
  • Lung
  • Subcellular fractions
  • Histochemistry
  • Perfusion
  • Endothelial cells
Nom du fichier dans la ressource
  • E. K?epela 1
  • J. Vi?car 2
  • L. Žižková 1
  • E. Kasafírek 3
  • Z. Kolá? 4
  • V. Lichnovský 4
  • 1) First Department of Medical Chemistry and Institute of Toxicology and Forensic Chemistry, Faculty of General Medicine, Charles University, 121 08, Prague
  • 2) Department of Medical Chemistry, Medical Faculty, Palacký University, 775 15, Olomouc
  • 3) Research Institute for Pharmacy and Biochemistry, 130 80, Prague
  • 4) Departments of Pathology and Histology and Embryology, Medical Faculty, Palacký University, 775 15, Olomouc, Czechoslovakia

Endothelial cells of the pulmonary circulation are equipped with an ectoenzyme protease system on their luminal surface. The membrane-bound proteases act on the circulating polypeptides and cleave certain peptide bonds in their structure, thus modifying their biological properties. We studied the enzyme dipeptidyl peptidase IV (DP-IV) in mammalian lungs in order to elucidate its contribution to the aforementioned proteolytic processing. We have found that lungs of mammalian species posses DP-IV with different levels of specific activity. In rat lungs the specific activity of DP-IV progressively increased during development between the 18th fetal and the 70th postnatal days. Human embryonal and fetal lungs had significantly higher specific activity of DP-IV compared with the lungs of adult individuals. The enzyme in lungs was mainly membrane bound and was solubilized by some detergents, but not with papain and trypsin. The Triton X-100-solubilized DP-IV from rat lung lysosomal-microsomal membranes migrated during electrophoresis on continuous 4–30% gradient polyacrylamide gel at native apparent Mr values of 260 000 and 490 000. Using a histochemical technique we found the enzyme activity of DP-IV in the capillary bed of the lung alveolar septa only. Four aminoacyl-L-proline-4-nitroanilide substrates for DP-IV were cleaved rapidly during one passage through isolated perfused blood-free rat lungs. The perfusion profiles of cleavage of these substrates were largely coincident with that of Blue Dextran 2 000, a compound, which is unlikely to leave the intravascular space. Taken together, the data suggest that DP-IV operates in vivo as a membrane-bound ectoenzyme on the luminal surface of pulmonary endothelial cells and that it may cleave certain circulating polypeptides.

Catégories Science-Metrix
  • 1 - health sciences
  • 2 - clinical medicine
  • 3 - respiratory system
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
Catégories Scopus
  • 1 - Health Sciences ; 2 - Medicine ; 3 - Pulmonary and Respiratory Medicine
Catégories WoS
  • 1 - science ; 2 - respiratory system
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  • Mammiferes
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