Nε-Acryloyllysine Piperazides as Irreversible Inhibitors of Transglutaminase 2: Synthesis, Structure-Activity Relationships, and Pharmacokinetic Profiling

J Med Chem. 2018 May 24;61(10):4528-4560. doi: 10.1021/acs.jmedchem.8b00286. Epub 2018 May 10.


Transglutaminase 2 (TGase 2)-catalyzed transamidation represents an important post-translational mechanism for protein modification with implications in physiological and pathophysiological conditions, including fibrotic and neoplastic processes. Consequently, this enzyme is considered a promising target for the diagnosis of and therapy for these diseases. In this study, we report on the synthesis and kinetic characterization of Nε-acryloyllysine piperazides as irreversible inhibitors of TGase 2. Systematic structural modifications on 54 new compounds were performed with a major focus on fluorine-bearing substituents due to the potential of such compounds to serve as radiotracer candidates for positron emission tomography. The determined inhibitory activities ranged from 100 to 10 000 M-1 s-1, which resulted in comprehensive structure-activity relationships. Structure-activity correlations using various substituent parameters accompanied by covalent docking studies provide an advanced understanding of the molecular recognition for this inhibitor class within the active site of TGase 2. Selectivity profiling of selected compounds for other transglutaminases demonstrated an excellent selectivity toward transglutaminase 2. Furthermore, an initial pharmacokinetic profiling of selected inhibitors was performed, including the assessment of potential membrane permeability and liver microsomal stability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Catalysis
  • Catalytic Domain
  • Enzyme Inhibitors / pharmacokinetics*
  • Enzyme Inhibitors / pharmacology*
  • GTP-Binding Proteins / antagonists & inhibitors*
  • Humans
  • Kinetics
  • Lysine / analogs & derivatives
  • Lysine / pharmacokinetics
  • Lysine / pharmacology
  • Mice
  • Microsomes, Liver / drug effects
  • Microsomes, Liver / enzymology*
  • Models, Molecular
  • Molecular Structure
  • Protein Conformation
  • Protein Glutamine gamma Glutamyltransferase 2
  • Pyridazines / chemistry*
  • Structure-Activity Relationship
  • Tissue Distribution
  • Transglutaminases / antagonists & inhibitors*


  • Enzyme Inhibitors
  • Pyridazines
  • piperazic acid
  • Protein Glutamine gamma Glutamyltransferase 2
  • Transglutaminases
  • GTP-Binding Proteins
  • Lysine