ABSTRACT
A lead generation and optimization program delivered the highly selective and potent CatC inhibitor 10 as an in vivo tool compound and potential development candidate. Structural studies were undertaken to generate SAR understanding.
Subject(s)
Cathepsin C/antagonists & inhibitors , Protease Inhibitors/chemical synthesis , Protease Inhibitors/pharmacology , Humans , Indicators and Reagents , Models, Molecular , Molecular Conformation , Recombinant Proteins/chemistry , Spectrometry, Fluorescence , Structure-Activity Relationship , Substrate Specificity , X-Ray DiffractionABSTRACT
Myeloperoxidase (MPO) is a prime candidate for promoting oxidative stress during inflammation. This abundant enzyme of neutrophils uses hydrogen peroxide to oxidize chloride to highly reactive and toxic chlorine bleach. We have identified 2-thioxanthines as potent mechanism-based inactivators of MPO. Mass spectrometry and x-ray crystal structures revealed that these inhibitors become covalently attached to the heme prosthetic groups of the enzyme. We propose a mechanism whereby 2-thioxanthines are oxidized, and their incipient free radicals react with the heme groups of the enzyme before they can exit the active site. 2-Thioxanthines inhibited MPO in plasma and decreased protein chlorination in a mouse model of peritonitis. They slowed but did not prevent neutrophils from killing bacteria and were poor inhibitors of thyroid peroxidase. Our study shows that MPO is susceptible to the free radicals it generates, and this Achilles' heel of the enzyme can be exploited to block oxidative stress during inflammation.
Subject(s)
Enzyme Inhibitors , Neutrophils/enzymology , Oxidative Stress/drug effects , Peritonitis/enzymology , Peroxidase , Xanthines , Animals , Crystallography, X-Ray , Disease Models, Animal , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Humans , Inflammation/drug therapy , Inflammation/ethnology , Inflammation/microbiology , Inflammation/pathology , Mice , Neutrophils/pathology , Oxidation-Reduction/drug effects , Peritonitis/drug therapy , Peritonitis/pathology , Peroxidase/antagonists & inhibitors , Peroxidase/chemistry , Peroxidase/metabolism , Xanthines/chemistry , Xanthines/pharmacologyABSTRACT
The investigation of drug metabolism requires substantial amount of metabolites. Isolation from urine is tedious, therefore, the material obtained by synthesis is preferred. Substantial amounts of three tentative drug metabolites, phenolic glucuronides, have been prepared using easily available glycosyl donors. The final products [3(2-N-methyl-N-isopropylaminoethoxy)phenyl] beta-D-glucopyranosiduronic acid, 4-amino-3,5-dimethylphenyl beta-D-glucopyranosiduronic acid and [2(S)-propanoyl-6-O-naphthyl] beta-D-glucopyranuronic acid are useful as, for example, reference material in metabolite investigations.
