{"title":"Chemical mechanisms of lipid peroxidation","authors":"Ned A. Porter","doi":"10.1016/j.rbc.2025.100054","DOIUrl":"10.1016/j.rbc.2025.100054","url":null,"abstract":"<div><div>The chemical framework for free radical chain oxidation of naturally-occurring lipids, commonly referred to as peroxidation, has provided a basis for understanding important processes in biology. H-atom transfer to peroxyl free radicals and olefin addition of those radicals are the primary rate-determining steps in peroxidation, but the lipid carbon radicals generated in these primary steps have multiple mechanistic pathways available. Oxygen addition, homolytic intramolecular substitution (<em>s</em><sub><em>H</em></sub><em>i</em>) and various cyclization reactions of intermediate peroxyl and alkoxyl radicals leads to a diverse set of products from polyunsaturated fatty acids and phospholipid esters. 5,7-Diene sterols are particularly reactive H-atom donors and give rise to complex product mixtures. The mechanistic guidelines for the important transformations of lipid peroxidation are summarized here and the connection between these fundamental chemical conversions and important enzymatic and non-enzymatic biological processes are outlined.</div></div>","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"12 ","pages":"Article 100054"},"PeriodicalIF":0.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144178655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Methionine oxidation products as biomarkers of oxidative damage to proteins and modulators of cellular metabolism and toxicity","authors":"Michael J. Davies","doi":"10.1016/j.rbc.2025.100052","DOIUrl":"10.1016/j.rbc.2025.100052","url":null,"abstract":"<div><div>Proteins are highly abundant and readily oxidized targets of reactive species formed in biological systems, with these often accounting for greater than 50 % of the dry mass of biological samples. Of the amino acids present in proteins, the sulfur-containing amino acids cysteine (Cys), cystine and methionine (Met) are some of the most reactive species with a range of biologically-relevant modifying agents including radicals, two-electron species and also many electrophiles. Reaction with Cys gives a wide range of both reversible and irreversible species. Lesser numbers of products are well-characterized for cystine and Met. For the latter, the sulfoxide is often the most abundant product, but other species including the cyclic species dehydromethionine, and methionine sulfone have been characterized and shown to be major species under some circumstances. Whilst the sulfone has been widely reported to arise from the sulfoxide as a result of further oxidation, increasing evidence suggests that it can also be formed directly, without the intermediacy of the sulfoxide, and particularly with singlet oxygen (<sup>1</sup>O<sub>2</sub>). Whilst the sulfoxide is subject to reduction (e.g. via methionine sulfoxide reductases) and further metabolism <em>in vivo</em>, the sulfone appears to be a stable product and may therefore under certain circumstances be a biomarker of Met oxidation. This article briefly reviews the oxidation chemistry of Cys and cystine, and a more detailed discussion of the mechanisms of Met oxidation, formation of the sulfoxide, dehydromethionine and sulfone, and the biological fates and activities of these species.</div></div>","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"12 ","pages":"Article 100052"},"PeriodicalIF":0.0,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huan Liu , Lusine Tonoyan , Béla Reiz , Arno G. Siraki
{"title":"Amplex Red cellular uptake produces radical intermediates by myeloperoxidase and mediates oxidative stress","authors":"Huan Liu , Lusine Tonoyan , Béla Reiz , Arno G. Siraki","doi":"10.1016/j.rbc.2025.100051","DOIUrl":"10.1016/j.rbc.2025.100051","url":null,"abstract":"<div><div>Amplex Red (AR) is commonly used to detect extracellular hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and is considered a cell-impermeable compound. However, it would appear capable of entering cells based on its phenoxazine substructure and the report of its mitochondrial membrane permeability. Additionally, myeloperoxidase (MPO) oxidation of AR produces a fluorescent compound, resorufin, which has been reported, though the mechanism is not well-studied. EPR spin trapping using glutathione (GSH) revealed that AR metabolism produced AR radicals and glutathionyl radicals (GS<sup>•</sup>). An intermediate metabolite, 3,7-dihydroxyphenoxazine, was observed by liquid chromatography-mass spectrometry (LC-MS), which supported AR radical disproportionation first and subsequently N-oxidation. Besides, in the presence of GSH, the formation of resorufin decreased significantly evidencing the reactivity of radical intermediates. Three types of AR-GS adduct were found using LC-MS and the resorufin GS-adduct was the dominant one. Regarding intracellular findings in HL-60 cells (that highly express MPO), LC-MS and fluorescence analysis showed AR penetrated the cell membrane and was oxidized by cellular MPO. Interestingly, we demonstrated that the oxidation of AR in HL-60 cells showed a significant time dependence; PF-1355, an MPO inhibitor, inhibited the oxidation of AR by MPO. Cell viability (ATP) revealed that 200 μM AR significantly decreased viability in HL-60 cells in 6 h. We also found that AR-mediated decreased total GSH and increased protein-radical formation. These findings revealed that AR is cell-permeable, and AR radicals induce cellular oxidative distress and lead to the formation of protein radicals, which correlate with the MPO-mediated mechanism of cytotoxicity.</div></div>","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"12 ","pages":"Article 100051"},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Ignasiak , K.J. Frąckowiak , E. Fuentes-Lemus , P.M. Hägglund , L. Gamon , M.J. Davies , Ł. Marczak , B. Marciniak
{"title":"Iodide influences the sensitized one-electron photo-oxidation of Tyr and Trp residues by competition reaction","authors":"M. Ignasiak , K.J. Frąckowiak , E. Fuentes-Lemus , P.M. Hägglund , L. Gamon , M.J. Davies , Ł. Marczak , B. Marciniak","doi":"10.1016/j.rbc.2025.100050","DOIUrl":"10.1016/j.rbc.2025.100050","url":null,"abstract":"<div><div>3-carboxybenzophenone (CB) is an efficient photosensitizer that can oxidize multiple amino acid side chains in peptides and proteins <em>via</em> electron transfer (ET) reactions yielding various radicals and radical ions. Recombination reactions of these species can yield CBH-adducts and cross-links, whereas secondary reactions can give radicals on other side chains and further products. Prevention of initial radical formation, or interception of intermediate radicals is predicted to modulate the extent of protein damage. Consequently, in this work the effect of iodide ions (I‾) on CB-photosensitized oxidation was investigated with Trp and TyrOH, as these moieties are prone to photooxidation. A scavenging effect of I‾ on the formation of TyrO<sup>•</sup> radicals was readily detected in kinetic experiments using laser flash photolysis, whilst effects on TrpN<sup>•</sup> radical formation remain ambiguous (due to overlap of the absorptions of transient absorption spectra of TrpN<sup>•</sup> and CBH<sup>•</sup> radicals). Addition of I‾ suppresses oxidation of Trp and TyrOH, with this resulting in lower concentrations of di-Trp, di-Tyr and adducts with CBH, without formation of additional products involving I‾. The effect of I‾ was also analysed for a model protein – lysozyme – with a protective effect observed against loss of activity on illumination with CB. Multiple products were identified, including adducts of CBH to Trp, TyrOH or Met. The formation of crosslinks arising from CB-mediated photo-oxidation of lysozyme was limited in the presence of I‾. Together these data indicate that I‾ modulates photodamage induced by CB to peptide and protein targets.</div></div>","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"12 ","pages":"Article 100050"},"PeriodicalIF":0.0,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chryssostomos Chatgilialoglu , Bronisław Marciniak , Krzysztof Bobrowski
{"title":"Properties of disulfide radical anions and their reactions in chemistry and biology","authors":"Chryssostomos Chatgilialoglu , Bronisław Marciniak , Krzysztof Bobrowski","doi":"10.1016/j.rbc.2024.100046","DOIUrl":"10.1016/j.rbc.2024.100046","url":null,"abstract":"<div><div>Disulfide radical anions (RSSR<sup>•−</sup>) derive both from the direct electron attachment to disulfide-containing compounds and the reaction of thiyl radicals with thiolate, being also reversible (RS<sup>•</sup> + RS<sup>−</sup> ⇆ RSSR<sup>•−</sup>). The investigation of these reactive intermediates started in 1960s by pulse radiolysis (PR) technique and electron spin resonance (ESR) spectroscopy, and more recently, their generation was studied in organic chemistry and biological mechanisms. The present review addresses a compendium on structural, chemical and spectroscopical properties of disulfide radical anions, as well as their involvement in synthetical and biological processes. Particular emphasis is given to disulfide moieties as reactive sites in proteins, and to the generation of small sulfur-centered radicals, connected to the discovery of a mechanism of tandem protein-lipid damage. Other important biologically related processes involving disulfide radical anions are treated in the review, such as: its formation from the glutathione thiyl radical GS<sup>•</sup> (GS<sup>•</sup> + GS<sup>−</sup> ⇆ GSSG<sup>•−</sup>), resulting from the antioxidant reactivity of glutathione (GSH/GS<sup>–</sup>), and the reduction of a ketone moiety by the disulfide radical anion at the active site of the enzymes ribonucleotide reductase (RNRs), the latter used for establishing a bioinspired reduction process in organic synthesis.</div></div>","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"11 ","pages":"Article 100046"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Enzymes of glycolysis and the pentose phosphate pathway as targets of oxidants: Role of redox reactions on the carbohydrate catabolism","authors":"Eduardo Fuentes-Lemus , Karen Usgame , Angélica Fierro , Camilo López-Alarcón","doi":"10.1016/j.rbc.2025.100049","DOIUrl":"10.1016/j.rbc.2025.100049","url":null,"abstract":"<div><div>Redox reactions can modulate metabolic and signaling pathways with consequences on cellular adaptation to different stimuli. The abundance and structural features of some metabolic enzymes make these targets of oxidants, including one- and two-electron oxidant molecules, altering their structure and/or function. Therefore, redox processes play an important role in physiology and pathology. In particular, the oxidative post-translational modification of the enzymes that participate in glycolysis and the pentose phosphate pathway (PPP) can modulate the carbon flux affecting synthesis of nucleotides, as well as production of adenosine triphosphate (ATP) and reducing equivalents (in the form of nicotinamide adenine dinucleotide phosphate, NADPH). Specifically, generation of NADPH, a cofactor important for cell homeostasis, is key to the management of the redox status of cells towards oxidative insults. In this review we discuss the available literature on the impact of oxidative post-translational modifications on key glycolytic and PPP enzymes with an analysis of the consequences these may have for cell metabolic adaptation. We also discuss the contributions of new experimental and <em>in silico</em> approaches to the redox biochemistry field, which have significantly illuminated the intricate relationship between the pathways involved in carbohydrate metabolism and how these could be regulated by redox reactions.</div></div>","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"11 ","pages":"Article 100049"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ana C. Lopez , Silvina Acosta , Mauricio Mastrogiovanni , Williams Porcal , María Magdalena Portela , Rosario Durán , Rafael Radi , Ana Denicola , Matias N. Möller
{"title":"Formation of protein-derived electrophiles in ribonuclease A by biologically relevant oxidants","authors":"Ana C. Lopez , Silvina Acosta , Mauricio Mastrogiovanni , Williams Porcal , María Magdalena Portela , Rosario Durán , Rafael Radi , Ana Denicola , Matias N. Möller","doi":"10.1016/j.rbc.2025.100048","DOIUrl":"10.1016/j.rbc.2025.100048","url":null,"abstract":"<div><div>Oxidative modifications in proteins have been extensively studied and found to increase in diabetes, cardiovascular diseases, neurodegenerative diseases, and aging. Some of the most studied modifications include the nitration of tyrosine and the formation of carbonyls in proteins. Tyrosine can also be oxidized to 3-(1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl)-L-alanine (HOCHDA) by several biologically relevant systems, a product that is electrophilic and reactive to biological nucleophiles such as glutathione. Herein, we characterized the reaction of a peptide containing HOCHDA with fluorescein-tagged glutathione by HPLC and mass spectrometry. To explore the possibility that the formation of oxidation-derived electrophiles occurs in proteins, we oxidized the tyrosine-rich, small protein, ribonuclease A, by different biologically relevant oxidizing systems and used fluorescein-tagged glutathione as the nucleophilic reagent. Oxidation of ribonuclease A with singlet oxygen, known to generate HOCHDA efficiently, generated an electrophile that reacted with fluorescein-tagged glutathione and was resistant to reduction by dithiothreitol. The amount of fluorescein-glutathione attached to the protein was quantified by gel filtration HPLC. Other oxidants such as peroxyl radical (from AAPH), ferryl (from hydrogen peroxide reaction with Fe(II):EDTA), and peroxynitrite, also generated a modified protein that reacted with fluorescein-glutathione. Analysis by LC-MS/MS indicated the formation of mono-oxygenated tyrosyl residues and di-oxygenated histidyl residues after exposure of the protein to AAPH which are good candidates to be the electrophilic centers. The formation of electrophiles was a common feature in the reactions of oxidants with ribonuclease A and may constitute an underappreciated mechanism of protein oxidative modification.</div></div>","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"11 ","pages":"Article 100048"},"PeriodicalIF":0.0,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michael J. Davies (Joint Editor-in-Chief), Rafael Radi (Joint Editor-in-Chief)
{"title":"Editorial: Special issue celebrating the work of Prof. Christine C. Winterbourn","authors":"Michael J. Davies (Joint Editor-in-Chief), Rafael Radi (Joint Editor-in-Chief)","doi":"10.1016/j.rbc.2024.100045","DOIUrl":"10.1016/j.rbc.2024.100045","url":null,"abstract":"","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"10 ","pages":"Article 100045"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Special issue on “Peroxynitrite and Reactive Nitrogen Species” dedicated to the 25th anniversary of the nitric oxide Nobel Prize","authors":"Ari Zeida, Jacek Zielonka, Madia Trujillo","doi":"10.1016/j.rbc.2024.100044","DOIUrl":"10.1016/j.rbc.2024.100044","url":null,"abstract":"","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"10 ","pages":"Article 100044"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ann-Kathrin Weishaupt , Anna Gremme , Torben Meiners , Vera Schwantes , Karsten Sarnow , Alicia Thiel , Tanja Schwerdtle , Michael Aschner , Heiko Hayen , Julia Bornhorst
{"title":"Dysfunctional copper homeostasis in Caenorhabditis elegans affects genomic and neuronal stability","authors":"Ann-Kathrin Weishaupt , Anna Gremme , Torben Meiners , Vera Schwantes , Karsten Sarnow , Alicia Thiel , Tanja Schwerdtle , Michael Aschner , Heiko Hayen , Julia Bornhorst","doi":"10.1016/j.rbc.2024.100043","DOIUrl":"10.1016/j.rbc.2024.100043","url":null,"abstract":"<div><div>While copper (Cu) is an essential trace element for biological systems due to its redox properties, excess levels may lead to adverse effects partly due to overproduction of reactive species. Thus, a tightly regulated Cu homeostasis is crucial for health. Cu dyshomeostasis and elevated labile Cu levels are associated with oxidative stress and neurodegenerative disorders, but the underlying mechanisms have yet to be fully characterized. Here, we used <em>Caenorhabditis elegans</em> loss-of-function mutants of the Cu chaperone ortholog atox-1 and the Cu binding protein ortholog ceruloplasmin to model Cu dyshomeostasis, as they display a shifted ratio of total Cu towards labile Cu. We applied highly selective and sensitive techniques to quantify metabolites associated to oxidative stress with focus on mitochondrial integrity, oxidative DNA damage and neurodegeneration all in the context of a disrupted Cu homeostasis. Our novel data reveal elevated oxidative stress, compromised mitochondria displaying reduced ATP levels and cardiolipin content. Cu dyshomeostasis further induced oxidative DNA damage and impaired DNA damage response as well as neurodegeneration characterized by behavior and neurotransmitter analysis. Our study underscores the essentiality of a tightly regulated Cu homeostasis as well as mitochondrial integrity for both genomic and neuronal stability.</div></div>","PeriodicalId":101065,"journal":{"name":"Redox Biochemistry and Chemistry","volume":"10 ","pages":"Article 100043"},"PeriodicalIF":0.0,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}