In Vitro Reactivity of Carboxylic Acid-CoA Thioesters with Glutathione

Sidenius, Ulrik; Skonberg, Christian; Olsen, Jørgen; Hansen, Steen Honoré

doi:10.1021/tx034127o

Cited by 62 publications

(54 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results are consistent with an increasing number of reports showing that xenobiotic acyl-CoA thioesters are reactive electrophiles that contribute to covalent binding of carboxylic acid-containing compounds to liver proteins (Sallustio et al, 2000;Li et al, 2002a;Sidenius et al, 2004;Olsen et al, 2005Olsen et al, , 2007.…”

Section: Discussionsupporting

confidence: 92%

“…In the current study, the role of the chemically reactive acyl-CoA thioester metabolite in the formation of covalent adducts to hepatocyte protein was addressed. Acyl-CoA thioester intermediary metabolites of acidic drugs are more electrophilic (Huxtable, 1986) than their corresponding acyl glucuronide derivatives and are increasingly being investigated for their contribution to the transacylation of GSH and protein (Sallustio et al, 2000;Li et al, 2002a,b;Sidenius et al, 2004;Grillo et al, 2008).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Covalent Binding of Phenylacetic Acid to Protein in Incubations with Freshly Isolated Rat Hepatocytes

Grillo

Lohr²

2009

Drug Metab Dispos

View full text Add to dashboard Cite

ABSTRACT:Phenylacetic acid (PAA) represents a substructure of a class of nonsteroidal anti-inflammatory carboxylic acid-containing drugs capable of undergoing metabolic activation in the liver to acylcoenzyme A (CoA)-and/or acyl glucuronide-linked metabolites that are proposed to be associated with the formation of immunogenic, and hence potentially hepatotoxic, drug-protein adducts. Herein, we investigated the ability of PAA to undergo phenylacetyl-S-acyl-CoA thioester (PA-CoA)-mediated covalent binding to protein in incubations with freshly isolated rat hepatocytes in suspension. Thus, when hepatocytes were incubated with phenylacetic acid carboxy-14 C (100 M) and analyzed for PA-CoA formation and covalent binding of PAA to protein and over a 3-h time period, both PA-CoA formation and covalent binding to protein increased rapidly, reaching 1.3 M and 291 pmol equivalents/mg protein after 4 and 6 min of incubation, respectively. However, the covalent binding of PAA to protein was reversible and decreased by 72% at the 3-h time point. After 3 h of incubation, PAA was shown to be metabolized primarily to phenylacetyl-glycine amide (84%). No PAA-acyl glucuronide was detected in the incubation extracts. PA-CoA reacted readily with glutathione in buffer, forming PA-Sacyl-glutathione; however, this glutathione conjugate was not detected in hepatocyte incubation extracts. Coincubation of hepatocytes with lauric acid led to a marked inhibition of PA-CoA formation and a corresponding inhibition of covalent binding to protein. SDS-polyacrylamide gel electrophoresis analysis showed the formation of two protein adducts having molecular masses of ϳ29 and ϳ33 kDa. In summary, PA-CoA formation in rat hepatocytes leads to the highly selective, but reversible, covalent binding to hepatocyte proteins, but not to the transacylation of glutathione.

show abstract

Section: Discussionsupporting

confidence: 92%

mentioning

confidence: 99%

Covalent Binding of Phenylacetic Acid to Protein in Incubations with Freshly Isolated Rat Hepatocytes

Grillo

Lohr²

2009

Drug Metab Dispos

View full text Add to dashboard Cite

show abstract

“…2. This fragmentation pattern is similar to that described for other acyl-CoAs Li et al, 2002;Olsen et al, 2003b;Sidenius et al, 2004), including that of the structurally related nonsteroidal anti-inflammatory drug, zomepirac (Olsen et al, 2005). The retention time and MS/MS spectrum of a synthetic standard were similar to those seen in liver samples from rats that had received a dose of 100 mg/kg.…”

supporting

confidence: 75%

“…acyl-CoA-dependent metabolism of Tol is important to identify, because studies have shown that Tol-CoA reacts spontaneously with the thiol of glutathione, indicating that transacylating reactions may also occur in liver cells in vivo (Olsen et al, 2003a;Sidenius et al, 2004). Tol-Car is formed via the reactive Tol-CoA intermediate by carnitine acyl transferases, and its formation is therefore of mechanistic significance showing the formation of the corresponding reactive acyl-CoA.…”

Section: Discussionmentioning

confidence: 99%

“…In a recent study, it has been shown that the pyrrole moiety of Tol may undergo bioactivation to a reactive arene oxide (Chen et al, 2006). Other reports have shown that acyl-coenzyme A thioesters (acyl-CoAs) are also reactive electrophilic metabolites (Sallustio et al, 2000;Grillo and Benet, 2002;Sidenius et al, 2004). Acyl-CoAs are intermediates in amino acid conjugation, carnitine conjugation, fatty acid synthesis, and ␤-oxidation.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Studies on the Metabolism of Tolmetin to the Chemically Reactive Acyl-Coenzyme A Thioester Intermediate in Rats

Olsen

Li²,

Skonberg³

et al. 2007

Drug Metab Dispos

Self Cite

View full text Add to dashboard Cite

ABSTRACT:Carboxylic acids may be metabolized to acyl glucuronides and acyl-coenzyme A thioesters (acyl-CoAs), which are reactive metabolites capable of reacting with proteins in vivo. In this study, the metabolic activation of tolmetin (Tol) to reactive metabolites and the subsequent formation of Tol-protein adducts in the liver were studied in rats. Two hours after dose administration (100 mg/kg i.p.), tolmetin acyl-CoA (Tol-CoA) was identified by liquid chromatography-tandem mass spectrometry in liver homogenates. Similarly, the acyl-CoA-dependent metabolites tolmetin-taurine conjugate (Tol-Tau) and tolmetin-acyl carnitine ester (Tol-Car) were identified in rat livers. In a rat bile study (100 mg/kg i.p.), the S-acyl glutathione thioester conjugate was identified, providing further evidence of the formation of reactive metabolites such as Tol-CoA or Tol-acyl glucuronide (Tol-O-G), capable of acylating nucleophilic functional groups. Three rats were treated with clofibric acid (150 mg/kg/day i.p. for 7 days) before dose administration of Tol. This resulted in an increase in covalent binding to liver proteins from 0.9 nmol/g liver in control rats to 4.2 nmol/g liver in clofibric acidtreated rats. Similarly, levels of Tol-CoA increased from 0.6 nmol/g to 4.4 nmol/g liver after pretreatment with clofibric acid, whereas the formation of Tol-O-G and Tol-Tau was unaffected by clofibric acid treatment. However, Tol-Car levels increased from 0.08 to 0.64 nmol/g after clofibric acid treatment. Collectively, these results confirm that Tol-CoA is formed in vivo in the rat and that this metabolite can have important consequences in terms of covalent binding to liver proteins.Drugs with a carboxylate functional group can be metabolized to chemically reactive metabolites that react with nucleophilic amino acids of proteins to form drug-protein adducts (Boelsterli, 2002;Bailey and Dickinson, 2003). Tolmetin (Tol; 5-[4Ј-methylbenzoyl]-1-methylpyrrole-2-acetic acid) is an example of a carboxylic acidcontaining drug which, in humans, is partly metabolized to the acyl glucuronide (Hyneck et al., 1987). In vitro studies have shown that the tolmetin-acyl glucuronide (Tol-O-G) is a reactive metabolite that reacts with the amino acid side chains of lysine, arginine, and serine present in human serum albumin (Ding et al., 1993(Ding et al., , 1995.Covalent binding of Tol has also been studied in humans, where Tol-protein adducts have been detected in plasma (Hyneck et al., 1988;Zia-Amirhosseini et al., 1994). Tol-protein adducts in plasma were believed to result from reaction of the acyl glucuronide with plasma proteins, since a good correlation between covalent plasmaprotein adducts and exposure to Tol-O-G was observed (Hyneck et al., 1988). In the liver, other metabolic pathways may contribute to Tol-protein adduct formation. In a recent study, it has been shown that the pyrrole moiety of Tol may undergo bioactivation to a reactive arene oxide (Chen et al., 2006). Other reports have shown that acyl-coenzyme A thioesters (acyl-CoAs) a...

show abstract

Principles of Drug Metabolism

Dalvie

Testa

2021

Burger's Medicinal Chemistry and Drug Discovery

View full text Add to dashboard Cite

Metabolism is a complex process that involves enzymatic modification of drugs and xenobiotics and is one of the most important determinants of their fate in the body. Although the drug metabolism is considered a process of detoxification, the products of metabolism can play an important role in the pharmacology and toxicology of the parent drug. Studying the metabolism of newly synthesized molecules is a valuable strategy that allows one to identify the underlying problems, such as “soft spots,” or metabolic activation, that affect the systemic exposure of a molecule and safety and efficacy. Early investigative metabolism of new compounds has helped in assessing the bioactivation potential of these candidates and thus, avoid reactive metabolites or put mitigation strategies in place. Metabolism can also lead to pharmacologically active metabolites. These metabolites can have superior pharmacological, pharmacokinetic, and safety profiles compared to their parent drug and can therefore be developed as drugs. This chapter provides an overview of the enzymes involved in the metabolism of xenobiotics and the different metabolic pathways. An attempt has been made to illustrate these principles with pertinent example with a brief review of topics of potential interests to aspiring medicinal chemists namely, the factors that may influence biotransformation or applications to predict the sites of metabolism. While the medicinal chemists are not expected to possess a deep knowledge of the mechanistic aspects, the hope is that the principles outlined in this chapter will assist them in designing a better drug.

show abstract

In Vitro Reactivity of Carboxylic Acid-CoA Thioesters with Glutathione

Cited by 62 publications

References 25 publications

Covalent Binding of Phenylacetic Acid to Protein in Incubations with Freshly Isolated Rat Hepatocytes

Covalent Binding of Phenylacetic Acid to Protein in Incubations with Freshly Isolated Rat Hepatocytes

Studies on the Metabolism of Tolmetin to the Chemically Reactive Acyl-Coenzyme A Thioester Intermediate in Rats

Principles of Drug Metabolism

Contact Info

Product

Resources

About