Abstract
Carboxylic acid-containing drugs are metabolized mainly through the formation of glucuronide and coenzyme A esters. These conjugates have been suspected to be responsible for the toxicity of several nonsteroidal anti-inflammatory drugs because of the reactivity of the electrophilic ester bond. In the present study we investigated the reactivity of ketoprofenyl-acylglucuronide (KPF-OG) and ketoprofenyl-acyl-coenzyme A (KPF-SCoA) toward cytosolic rat liver glutathione S-transferases (GST). We observed that KPF-SCoA, but not KPF-OG inhibited the conjugation of 1-chloro-2,4-dinitrobenzene and 4-nitroquinoline N-oxide catalyzed by both purified cytosolic rat liver GST and GST from FAO and H5-6 rat hepatoma cell lines. Photoaffinity labeling with KPF-SCoA suggested that the binding of this metabolite may overlap the binding site of 4-methylumbelliferone sulfate. Furthermore, high-performance liquid chromatography and mass spectrometry analysis showed that both hydrolysis and transacylation reactions were observed in the presence of GST and glutathione. The formation of ketoprofenyl-S-acyl-glutathione could be kinetically characterized (apparent Km = 196.0 ± 70.6 μM). It is concluded that KPF-SCoA is both a GST inhibitor and a substrate of a GST-dependent transacylation reaction. The reactivity and inhibitory potency of thioester CoA derivatives toward GST may have potential implications on the reported in vivo toxicity of some carboxylic acid-containing drugs.
Footnotes
-
This work was supported in part by Région de Lorraine. S.O. is a recipient of a fellowship from Ministère de la Recherche et de l'Enseignement Supérieur (France).
-
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
-
doi:10.1124/dmd.107.016808.
-
ABBREVIATIONS: NSAID, nonsteroidal anti-inflammatory drug; KPF, ketoprofen (2-(3-benzoylphenyl) propionic acid); COX, cyclooxygenase; KPF-OG, ketoprofenyl-acylglucuronide; KPF-SCoA, ketoprofenyl-acyl-Coenzyme A; GST, glutathione S-transferase(s); GSH, glutathione reduced form; CDNB, 1-chloro-2,4-dinitrobenzene; NQO, 4-nitroquinoline N-oxide; HPLC, high-performance liquid chromatography; MALDI-TOF, matrix-assisted laser desorption ionization/time of flight; PSD, post source decay; MS, mass spectroscopy; KPF-SG, ketoprofenyl-S-acyl-glutathione; 4-MU sulfate, 4-methylumbelliferone sulfate.
- Received May 23, 2007.
- Accepted October 24, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
DMD articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|