Interaction of the electrophilic ketoprofenyl-glucuronide and ketoprofenyl-coenzyme A conjugates with cytosolic glutathione S-transferases.
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 K(m) = 196.0 +/- 70.6 microM). 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.
Osbild
Sandra
S
Laboratoire d'Ingénierie Moléculaire et Biochimie Pharmacologique, Institut Jean Barriol FR Centre National de la Recherche Scientifique 2843, Université Paul Verlaine-Metz, Metz, France.
Bour
Jérome
J
Maunit
Benoît
B
Guillaume
Cécile
C
Asensio
Carine
C
Muller
Jean-François
JF
Netter
Patrick
P
Kirsch
Glbert
G
Bagrel
Denyse
D
Lapicque
Françoise
F
Battaglia
Eric
E
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000378:metabolism*; D045744:Cell Line, Tumor; D003065:Coenzyme A / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D020719:Glucuronides / Q000378:metabolism*; D005978:Glutathione / Q000037:antagonists & inhibitors / Q000378:metabolism; D005982:Glutathione Transferase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007660:Ketoprofen / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D051381:Rats
D000894:Anti-Inflammatory Agents, Non-Steroidal; D020719:Glucuronides; D007660:Ketoprofen; D005982:Glutathione Transferase; D005978:Glutathione; D003065:Coenzyme A