Substance P and Bradykinin Are Natural Inhibitors of CD13/Aminopeptidase N Academic Article uri icon


MeSH Major

  • Antigens, CD13
  • Bradykinin
  • Substance P


  • Aminopeptidase N (EC is an important enzyme that is involved in the degradation of regulatory peptides including enkephalins. We report here that purified and native membrane-bound aminopeptidase N will sequentially and completely hydrolyze both Leu-enkephalin and Met-enkephalin from the amino terminus. Both purified pig aminopeptidase N and the enzyme on live HL60 cells displayed similar Km values for enkephalin. The naturally occurring neuropeptides substance P and bradykinin, and the morphine agonist, morphiceptin, were not hydrolyzed by aminopeptidase N and each inhibited the enzymatic activity. Each of these peptides contains a proline at the second residue. The Ki values for substance P (0.44 microM), bradykinin (9.4 microM), and morphiceptin (169 microM) were obtained with the enzyme on live HL60 cells. The values for the purified enzyme from pig were similar. The potent inhibition of aminopeptidase N by substance P and bradykinin suggests that these peptides may be natural inhibitors of the enzyme.

publication date

  • March 17, 1995



  • Academic Article



  • eng

Digital Object Identifier (DOI)

  • 10.1006/bbrc.1995.1390

PubMed ID

  • 7535053

Additional Document Info

start page

  • 664

end page

  • 74


  • 208


  • 2