When are metal ion-dependent hydroxyl and alkoxyl radical adducts of 5,5-dimethyl-1-pyrroline N-oxide artifacts?

Hanna, Phillip M.; Chamulitrat, Waleé; Mason, Ronald P.

doi:10.1016/0003-9861(92)90620-c

Cited by 118 publications

(86 citation statements)

References 10 publications

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“…EMPO was used instead of DMPO because the superoxide, hydroxyl, and thiyl radical adducts are more readily distinguished and because its superoxide radical adduct is more stable and does not spontaneously decay to a hydroxyl radical adduct signal (Olive et al, 2000;Zhang et al, 2000) as is observed with the DMPO-superoxide adduct (Thornalley, 1986;Makino et al, 1990;Hanna et al, 1992). We report that MAQ-NOH generated an EMPO-hydroxyl radical adduct (Fig.…”

Section: Discussionmentioning

confidence: 70%

Primaquine-Induced Hemolytic Anemia: Formation of Free Radicals in Rat Erythrocytes Exposed to 6-Methoxy-8-hydroxylaminoquinoline

Bolchoz

Gelasco

Jollow³

et al. 2002

J Pharmacol Exp Ther

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Primaquine is an important antimalarial drug that is often doselimited in therapy by the onset of hemolytic anemia. We have shown recently that an N-hydroxy metabolite of primaquine, 6-methoxy-8-hydroxylaminoquinoline (MAQ-NOH), is a directacting hemolytic agent in rat red cells and that the hemolytic activity of this metabolite is associated with GSH oxidation and oxidative damage to both membrane lipids and skeletal proteins. To determine whether the formation of free radicals may be involved in this process, rat red cells (40% suspensions) were incubated with hemolytic concentrations of MAQ-NOH (150 -750 M) and examined by EPR spectroscopy using 2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (EMPO) as a spin trap. Addition of MAQ-NOH to red cell suspensions containing 10 mM EMPO gave rise to an EPR spectrum with hyperfine constants consistent with those of an EMPO-hydroxyl radical adduct standard. Of interest, formation of EMPO-OH was constant for up to 20 min and dependent on the presence of erythrocytic GSH. Although no other radical adduct signals were detected in the cells by EPR, spectrophotometric analysis revealed the presence of ferrylhemoglobin, which indicates that hydrogen peroxide is generated under these experimental conditions. The data support the hypothesis that oxygen-derived and possibly other free radicals are involved in the mechanism underlying MAQ-NOH-induced hemolytic anemia.Hemolytic anemia and methemoglobinemia are well recognized dose-limiting side effects in the therapeutic use of arylamine drugs, such as primaquine and dapsone (Beutler, 1969). Because these compounds are not hemotoxic when incubated with red cells in vitro, it has long been appreciated that metabolites are responsible for the onset of the hemolytic response. In the cases of aniline (Harrison and Jollow, 1986), dapsone (Grossman and Jollow, 1988), and phenacetin (Jensen and Jollow, 1991), we have shown that the hemolytic metabolites are their N-hydroxy derivatives. Primaquine metabolism, on the other hand, is relatively more complex, and the metabolites that mediate the hemotoxic responses have not been identified. A variety of known and putative phenolic metabolites of primaquine are redox-active and therefore have the potential to mediate primaquine hemotoxicity (Strother et al., 1984;Baird et al., 1986;Fletcher et al., 1988;Agarwal et al., 1991); however, direct evidence for their hemolytic activity is lacking. We have recently explored an alternative hypothesis-that primaquine hemotoxicity is mediated by an N-hydroxylated metabolite, 6-methoxy-8-hydroxylaminoquinoline (MAQ-NOH).Although the mechanism underlying the damage and removal of red cells by hemolytic N-hydroxylamines remains unclear, oxidative stress has long been considered to play a prominent role in the process (for review, see Beutler, 1971). This concept is based on the well known association of hemotoxicity with oxidation of erythrocytic GSH (to glutathione disulfide and glutathione protein-mixed disulfides), with methemoglobin f...

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Section: Discussionmentioning

confidence: 70%

Primaquine-Induced Hemolytic Anemia: Formation of Free Radicals in Rat Erythrocytes Exposed to 6-Methoxy-8-hydroxylaminoquinoline

Bolchoz

Gelasco

Jollow³

et al. 2002

J Pharmacol Exp Ther

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“…3B, trace g ). Therefore, our data suggest that inp1 can yield DEPMPO/ Á OH: (a) metal-catalyzed nucleophilic addition of water occurring at the double bond of pyrroline N-oxides (20,(23)(24)(25) and (b) reduction of the protonated form of DEPMPO/O 2Á À by glutathione peroxidase (20,23,24). Because none of these two unspecific mechanisms can account for inhibitions by catalase and deferoxamine (Fig.…”

Section: Discussionmentioning

confidence: 86%

Tumor Protein 53–Induced Nuclear Protein 1 Is a Major Mediator of p53 Antioxidant Function

et al. 2008

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Abstractp53 exerts its tumor suppressor function mainly through transcriptional induction of target genes involved in several processes, including cell cycle checkpoints, apoptosis, and regulation of cell redox status. p53 antioxidant function is dependent on its transcriptional activity and proceeds by sequential induction of antioxidant and proapoptotic targets. However, none of the thus far renowned p53 targets have proved able to abolish on their own the intracellular reactive oxygen species (ROS) accumulation caused by p53 deficiency, therefore pointing to the existence of other prominent and yet unknown p53 antioxidant targets. Here, we show that TP53INP1 represents such a target. Indeed, TP53INP1 transcript induction on oxidative stress is strictly dependent on p53. Mouse embryonic fibroblasts (MEF) and splenocytes derived from TP53INP1-deficient (inp1 À/À ) mice accumulate intracellular ROS, whereas overexpression of TP53INP1 in p53-deficient MEFs rescues ROS levels to those of p53-proficient cells, indicating that TP53INP1 antioxidant function is p53 independent. Furthermore, accumulation of ROS in inp1 À/À cells on oxidant challenge is associated with decreased expression of p53 targets p21/Cdkn1a, Sesn2, TAp73, Puma, and Bax. Mutation of p53 Ser 58 (equivalent to human p53 Ser 46 ) abrogates transcription of these genes, indicating that TP53INP1-mediated p53 Ser 58 phosphorylation is implicated in this process. In addition, TP53INP1 deficiency results in an antioxidant (N-acetylcysteine)-sensitive acceleration of cell proliferation. Finally, TP53INP1 deficiency increases oxidative stress-related lymphoma incidence and decreases survival of p53 +/À mice. In conclusion, our data show that TP53INP1 is a major actor of p53-driven oxidative stress response that possesses both a p53-independent intracellular ROS regulatory function and a p53-dependent transcription regulatory function. [Cancer Res 2009;69(1):219-26]

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“…2). This result can be explained by the known ability of DMPO to chelate Cu(II) (29); however, as seen in Fig. 2D, HSA radicalderived nitrone adducts were enhanced by DMPO.…”

Section: Production Of Hsa Radicals By Copper-catalyzed Oxidation-resmentioning

confidence: 84%

“…To our knowledge, nobody has detected protein radicals in the well known system of human serum albumin (HSA)/ Cu(II)/H 2 O 2 . If such detection is possible by means of immunospin trapping (26,27) (see Scheme I), it would represent a notable advantage of this technique over the standard ESR techniques for detecting protein radicals, which are compromised by the broad ESR signal of Cu(II) (28,29). Thus, immunospin trapping could be a powerful tool for detecting protein radicals in complex systems such as cells.…”

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confidence: 99%

Copper-catalyzed Protein Oxidation and Its Modulation by Carbon Dioxide

Ramirez

Gomez-Mejiba

Mason

2005

Journal of Biological Chemistry

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It is well known that hydrogen peroxide (H 2 O 2 )-induced copper-catalyzed fragmentation of proteins follows a site-specific oxidative mechanism mediated by hydroxyl radical-like species (i.e. Cu(I)O, Cu(II)/ ⅐ OH or Cu(III)) that ends in increased carbonyl formation and protein fragmentation. We have found that the nitrone spin trap DMPO (5,5-dimethyl-1-pyrroline N-oxide) prevented such processes by trapping human serum albumin (HSA)-centered radicals, in situ and in real time, before they reacted with oxygen. When (bi)carbonate (CO 2 , H 2 CO 3 , HCO 3 ؊ , and CO 3 ؊2 ) was added to the reaction mixture, it blocked fragmentation mediated by hydroxyl radical-like species but enhanced DMPO-trappable radical sites in HSA. In the past, this effect would have been explained by oxidation of (bi)carbonate to a carbonate radical anion (CO 3 . ) by a bound hydroxyl rad-

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When are metal ion-dependent hydroxyl and alkoxyl radical adducts of 5,5-dimethyl-1-pyrroline N-oxide artifacts?

Cited by 118 publications

References 10 publications

Primaquine-Induced Hemolytic Anemia: Formation of Free Radicals in Rat Erythrocytes Exposed to 6-Methoxy-8-hydroxylaminoquinoline

Primaquine-Induced Hemolytic Anemia: Formation of Free Radicals in Rat Erythrocytes Exposed to 6-Methoxy-8-hydroxylaminoquinoline

Tumor Protein 53–Induced Nuclear Protein 1 Is a Major Mediator of p53 Antioxidant Function

Copper-catalyzed Protein Oxidation and Its Modulation by Carbon Dioxide

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