Human caspase-3 inhibition by Z-tLeu-Asp-H: tLeu(P2) counterbalances Asp(P4) and Glu(P3) specific inhibitor truncation

Patrizia Colantonio, Loris Leboffe, Alessandro Bolli, Maria Marino, Paolo Ascenzi, Grazia Luisi

Research output: Contribution to journalArticle

Abstract

Caspase-3 is responsible for the cleavage of several proteins including the nuclear enzyme poly(ADP-ribose) polymerase (PARP). Designed on the cleavage site of PARP, Ac-Asp-Glu-Val-Asp-H has been reported as a highly specific inhibitor. To overcome the susceptibility to proteolysis, the intrinsic instability, and the scarce membrane permeability of tetra-peptidyl aldehydes, di- and tri-peptidyl caspase-3 inhibitors have been synthesized. Here, the synthesis and the inhibition properties of peptidyl aldehydes Z-tLeu-Asp-H, Z-tLeu-Val-Asp-H, and Z-Val-tLeu-Asp-H are reported. Z-tLeu-Asp-H, Z-tLeu-Val-Asp-H, and Z-Val-tLeu-Asp-H inhibit competitively human caspase-3 activity in vitro with Ki 0 = 3.6 nM, 18.2 nM, and 109 nM, respectively (pH 7.4 and 25 °C). Moreover, Z-tLeu-Asp-H impairs apoptosis in human DLD-1 colon adenocarcinoma cells without affecting caspase-8. Therefore, Ac-Asp-Glu-Val-Asp-H can be truncated to Z-tLeu-Asp-H retaining nanomolar inhibitory activity in vitro and displaying action in whole cells, these properties reflect the unprecedented introduction of the bulky and lipophilic tLeu residue at the P2 position.

Original languageEnglish
Pages (from-to)757-762
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume377
Issue number3
DOIs
Publication statusPublished - Dec 19 2008

Keywords

  • Apoptosis
  • Caspase-3
  • Enzyme competitive inhibition
  • Human DLD-1 colon adenocarcinoma cells
  • Peptidyl aldehyde inhibitor
  • tert-Leucine

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Cell Biology
  • Molecular Biology

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