Small peptide inhibitors of acetyl-peptide hydrolase having an uncommon mechanism of inhibition and a stable bent conformation

J Med Chem. 2012 Mar 8;55(5):2102-11. doi: 10.1021/jm2013375. Epub 2012 Feb 21.


Acyl peptide hydrolase (APEH) catalyzes the removal of acetyl-amino acids from the N-terminus of peptides and cytoplasmic proteins. Due to the role played in several diseases, and to the growing interest around N-terminal acetylation, studies on APEH structure, function, and inhibition are attracting an ever increasing attention. We have therefore screened a random tetrapeptide library, N-capped with selected groups, and identified a trifluoroacetylated tetrapeptide (CF(3)-lmph) which inhibits the enzyme with a K(i) of 24.0 ± 0.8 μM. The inhibitor is selective for APEH, shows an uncommon uncompetitive mechanism of inhibition, and in solution adopts a stable bent conformation. CF(3)-lmph efficiently crosses cell membranes, blocking the cytoplasmic activity of APEH; however, it triggers a mild pro-apoptotic effect as compared to other competitive and noncompetitive inhibitors. The unusual inhibition mechanism and the stable structure make the new compound a novel tool to investigate enzyme functions and a useful scaffold to develop more potent inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects
  • Cell Line, Tumor
  • Cell Membrane Permeability
  • Circular Dichroism
  • Humans
  • Molecular Dynamics Simulation
  • Oligopeptides / chemistry*
  • Oligopeptides / metabolism
  • Oligopeptides / pharmacology
  • Peptide Hydrolases / chemistry*
  • Peptide Library
  • Protease Inhibitors / chemistry*
  • Protease Inhibitors / metabolism
  • Protease Inhibitors / pharmacology
  • Protein Conformation
  • Structure-Activity Relationship


  • Oligopeptides
  • Peptide Library
  • Protease Inhibitors
  • Peptide Hydrolases
  • acylaminoacyl-peptidase