Neuropeptide-processing carboxypeptidases

Suwen Wei, Yun Feng, Elena Kalinina, Lloyd D. Fricker

Research output: Contribution to journalArticle

21 Scopus citations


Neuropeptides are generally produced from precursor proteins by selective cleavage at specific sites, usually involving basic amino acids. Enzymes such as the prohormone convertases and carboxypeptidase E are highly specific for these basic amino acid-containing sites. In addition to this "traditional" pathway, several neuropeptides are known to be cleaved at non-basic sites, and the enzymes responsible for these cleavages have not been conclusively identified. In a recent search for novel members of the metallocarboxypeptidase family, we found three human genes. One of these, named "CPA-5," has a specificity for C-terminal hydrophobic amino acids and mRNA expression in brain, pituitary, and testis. To test whether CPA-5 protein has a distribution pattern in pituitary that is consistent with a role for this enzyme in the non-basic processing of proopiomelanocortin-derived peptides such as beta-endorphin and adrenocorticotropin, we examined the distribution of CPA-5 using immunocytochemistry. In the pituitary, CPA-5 is detected in the neurointermediate lobe and in scattered cells in the anterior lobe. In the AtT-20 corticotroph cell line, CPA-5 has a perinuclear distribution. Taken together, these results are consistent with a role for CPA-5 in the intracellular processing of proopiomelanocortin-derived peptides at non-basic sites.

Original languageEnglish (US)
Pages (from-to)655-662
Number of pages8
JournalLife Sciences
Issue number6
StatePublished - Jun 27 2003


  • Carboxypeptidase A-5
  • Carboxypeptidase E
  • Enkephalin convertase
  • Metallocarboxypeptidase
  • Peptide processing

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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