Degradation of Dynorphin‐Related Peptides by the Puromycin‐Sensitive Aminopeptidase and Aminopeptidase M

Afshin Safavi, Louis B. Hersh

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

Abstract: The degradation of dynorphin‐related peptides by the puromycin‐sensitive aminopeptidase and aminopeptidase M was examined using these peptides as alternate substrate inhibitors. Ki determinations showed that both aminopeptidases exhibit a higher affinity for longer dynorphin‐related peptides, i.e., Ki for dynorphin A‐17 = 23–30 nM with the Ki increasing to 25–50 µM for the enkephalin pentapeptides. Binding appears dependent not only on peptide length, but also on its sequence. With aminopeptidase M, as the peptide size increases from five to 10 amino acids, kcat remains relatively constant; however, as the peptide size increases beyond a decapeptide, kcat decreases significantly. With the puromycin‐sensitive aminopeptidase, similar results were obtained except that kcat was greatest for the pentapeptide. Thus, if one considers kcat/Km as the relevant kinetic constant for estimating in vivo peptide hydrolysis, these results are consistent with the involvement of aminopeptidase M and the puromycin‐sensitive aminopeptidase in the degradation of extended dynorphin‐related peptides.

Original languageEnglish
Pages (from-to)389-395
Number of pages7
JournalJournal of Neurochemistry
Volume65
Issue number1
DOIs
StatePublished - Jul 1995

Keywords

  • Aminopeptidase
  • Des‐tyrosyl dynorphins
  • In vivo metabolism

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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