Neuropeptide-processing carboxypeptidases

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

Research output: Contribution to journalArticlepeer-review

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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