Immunohistochemical localization of carboxypeptidasese E and D in the human placenta and umbilical cord

Sandra E. Reznik, Carolyn M. Salafia, Janice M. Lage, Lloyd D. Fricker

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Carboxypeptidase E (CPE) is highly concentrated in neuroendocrine tissues and is the only carboxypeptidase detected in mature secretory vesicles. Carboxypeptidase D (CPD), a carboxypeptidase with CPE-like activity, is widely distributed in tissues and is present in the trans-Golgi network. Previous work had shown that both CPE and CPD are expressed in the human placenta and that CPD is expressed at much higher levels than CPE. The present work provides evidence for the co-localization of CPE and CPD to basal plate extravillous trophoblasts and maternal uteroplacental vascular endothelial cells, chorionic villous endothelial cells, amnionic epithelial cells, and umbilical venous and arterial smooth muscle cells. Whereas the intensity of CPD immunostaining is similar in the placenta and umbilical cord, CPE staining in the placenta is much weaker than in the umbilical cord, suggesting that CPD plays a more important role in the processing of placental peptides. Immunoelectron microscopy of umbilical venous smooth muscle cells shows subcellular localization of both enzymes to the rough endoplasmic reticulum. In addition, CPE is present just subjacent to the cell membrane. The difference in cellular and subcellular localization between the two enzymes indicates that they perform distinct functions in the processing of placental peptides and proteins.

Original languageEnglish (US)
Pages (from-to)1359-1367
Number of pages9
JournalJournal of Histochemistry and Cytochemistry
Issue number12
StatePublished - Dec 1998


  • Carboxypeptidase D (CPD)
  • Carboxypeptidase E (CPE)
  • Immunoelectron microscopy
  • Immunohistochemistry
  • Placenta
  • Umbilical cord

ASJC Scopus subject areas

  • Anatomy
  • Histology


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