Articoli di riviste: "Proteins Oxidation"

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Pattison, David I., Aldwin Suryo Rahmanto e Michael J. Davies. "Photo-oxidation of proteins". Photochem. Photobiol. Sci. 11, n. 1 (2012): 38–53. http://dx.doi.org/10.1039/c1pp05164d.

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FU, Shanlin, Min-Xin FU, W. John BAYNES, R. Suzanne THORPE e T. Roger DEAN. "Presence of dopa and amino acid hydroperoxides in proteins modified with advanced glycation end products (AGEs): amino acid oxidation products as a possible source of oxidative stress induced by AGE proteins". Biochemical Journal 330, n. 1 (15 febbraio 1998): 233–39. http://dx.doi.org/10.1042/bj3300233.

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Glycation and subsequent Maillard or browning reactions of glycated proteins, leading to the formation of advanced glycation end products (AGEs), are involved in the chemical modification of proteins during normal aging and have been implicated in the pathogenesis of diabetic complications. Oxidative conditions accelerate the browning of proteins by glucose, and AGE proteins also induce oxidative stress responses in cells bearing AGE receptors. These observations have led to the hypothesis that glycation-induced pathology results from a cycle of oxidative stress, increased chemical modification of proteins via the Maillard reaction, and further AGE-dependent oxidative stress. Here we show that the preparation of AGE-collagen by incubation with glucose under oxidative conditions in vitro leads not only to glycation and formation of the glycoxidation product Nε-(carboxymethyl)lysine (CML), but also to the formation of amino acid oxidation products on protein, including m-tyrosine, dityrosine, dopa, and valine and leucine hydroperoxides. The formation of both CML and amino acid oxidation products was prevented by anaerobic, anti-oxidative conditions. Amino acid oxidation products were also formed when glycated collagen, prepared under anti-oxidative conditions, was allowed to incubate under aerobic conditions that led to the formation of CML. These experiments demonstrate that amino acid oxidation products are formed in proteins during glycoxidation reactions and suggest that reactive oxygen species formed by redox cycling of dopa or by the metal-catalysed decomposition of amino acid hydroperoxides, rather than by redox activity or reactive oxygen production by AGEs on protein, might contribute to the induction of oxidative stress by AGE proteins.

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Burgoyne, Joseph R., e Philip Eaton. "Contemporary techniques for detecting and identifying proteins susceptible to reversible thiol oxidation". Biochemical Society Transactions 39, n. 5 (21 settembre 2011): 1260–67. http://dx.doi.org/10.1042/bst0391260.

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Elevated protein oxidation is a widely reported hallmark of most major diseases. Historically, this ‘oxidative stress’ has been considered causatively detrimental, as the protein oxidation events were interpreted simply as damage. However, recent advances have changed this antiquated view; sensitive methodology for detecting and identifying proteins susceptible to oxidation has revealed a fundamental role for this modification in physiological cell signalling during health. Reversible protein oxidation that is dynamically coupled with cellular reducing systems allows oxidative protein modifications to regulate protein function, analogous to phosphoregulation. However, the relatively labile nature of many reversible protein oxidation states hampers the reliable detection and identification of modified proteins. Consequently, specialized methods to stabilize protein oxidation in combination with techniques to detect specific types of modification have been developed. Here, these techniques are discussed, and their sensitivity, selectivity and ability to reliably identify reversibly oxidized proteins are critically assessed.

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Pandey, Kanti Bhooshan, Mohd Murtaza Mehdi, Pawan Kumar Maurya e Syed Ibrahim Rizvi. "Plasma Protein Oxidation and Its Correlation with Antioxidant Potential During Human Aging". Disease Markers 29, n. 1 (2010): 31–36. http://dx.doi.org/10.1155/2010/964630.

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Previous studies have indicated that the main molecular characteristic of aging is the progressive accumulation of oxidative damages in cellular macromolecules. Proteins are one of the main molecular targets of age-related oxidative stress, which have been observed during aging process in cellular systems. Reactive oxygen species (ROS) can lead to oxidation of amino acid side chains, formation of protein-protein cross-linkages, and oxidation of the peptide backbones. In the present study, we report the age-dependent oxidative alterations in biomarkers of plasma protein oxidation: protein carbonyls (PCO), advanced oxidation protein products (AOPPs) and plasma total thiol groups (T-SH) in the Indian population and also correlate these parameters with total plasma antioxidant potential. We show an age dependent decrease in T-SH levels and increase in PCO and AOPPs level. The alterations in the levels of these parameters correlated significantly with the total antioxidant capacity of the plasma. The levels of oxidized proteins in plasma provide an excellent biomarker of oxidative stress due to the relative long half-life of such oxidized proteins.

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Rogers, K. R., C. J. Morris e D. R. Blake. "Oxidation of thiol in the vimentin cytoskeleton". Biochemical Journal 275, n. 3 (1 maggio 1991): 789–91. http://dx.doi.org/10.1042/bj2750789.

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Sublethal doses of H2O2, which induces oxidative stress, cause substantial alteration to the vimentin cytoskeleton in various cell types. We have used a thiol-blot assay to assess thiol status in individual proteins from cell extracts. Vimentin thiol is oxidized in preference to other cytoskeleton proteins. Immunoblot analysis also demonstrated a loss of reactivity to an anti-vimentin monoclonal antibody under non-reducing conditions, possibly due to thiol-group oxidation. During induced oxidative stress a number of proteins become associated with the cytoskeleton extracts.

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Lawal, Remilekun O., Fabrizio Donnarumma e Kermit K. Murray. "Electrospray Photochemical Oxidation of Proteins". Journal of The American Society for Mass Spectrometry 30, n. 11 (5 settembre 2019): 2196–99. http://dx.doi.org/10.1007/s13361-019-02313-4.

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Hambly, David M., e Michael L. Gross. "Cold Chemical Oxidation of Proteins". Analytical Chemistry 81, n. 17 (settembre 2009): 7235–42. http://dx.doi.org/10.1021/ac900855f.

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Simpson, Richard J. "Performic Acid Oxidation of Proteins". Cold Spring Harbor Protocols 2007, n. 3 (marzo 2007): pdb.prot4698. http://dx.doi.org/10.1101/pdb.prot4698.

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Luna, Carolina, e Mario Estévez. "Oxidative damage to food and human serum proteins: Radical-mediated oxidation vs. glyco-oxidation". Food Chemistry 267 (novembre 2018): 111–18. http://dx.doi.org/10.1016/j.foodchem.2017.06.154.

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Bruckbauer, Steven T., Benjamin B. Minkoff, Michael R. Sussman e Michael M. Cox. "Proteome Damage Inflicted by Ionizing Radiation: Advancing a Theme in the Research of Miroslav Radman". Cells 10, n. 4 (20 aprile 2021): 954. http://dx.doi.org/10.3390/cells10040954.

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Oxidative proteome damage has been implicated as a major contributor to cell death and aging. Protein damage and aging has been a particular theme of the recent research of Miroslav Radman. However, the study of how cellular proteins are damaged by oxidative processes is still in its infancy. Here we examine oxidative changes in the proteomes of four bacterial populations—wild type E. coli, two isolates from E. coli populations evolved for high levels of ionizing radiation (IR) resistance, and D. radiodurans—immediately following exposure to 3000 Gy of ionizing radiation. By a substantial margin, the most prominent intracellular oxidation events involve hydroxylation of methionine residues. Significant but much less frequent are carbonylation events on tyrosine and dioxidation events on tryptophan. A few proteins are exquisitely sensitive to targeted oxidation events, notably the active site of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in E. coli. Extensive experimental evolution of E. coli for IR resistance has decreased overall proteome sensitivity to oxidation but not to the level seen in D. radiodurans. Many observed oxidation events may reflect aspects of protein structure and/or exposure of protein surfaces to water. Proteins such as GAPDH and possibly Ef-Tu may have an evolved sensitivity to oxidation by H2O2.

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CZAPSKI, Grzegorz A., Diana AVRAM, Dmitri V. SAKHAROV, Karel W. A. WIRTZ, Joanna B. STROSZNAJDER e Everard H. W. PAP. "Activated neutrophils oxidize extracellular proteins of endothelial cells in culture: effect of nitric oxide donors". Biochemical Journal 365, n. 3 (1 agosto 2002): 897–902. http://dx.doi.org/10.1042/bj20011206.

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Protein oxidation of human umbilical-vein endothelial cells (HUVEC) in culture was examined under various conditions of oxidative stress. Extracellular protein (ECP) oxidation was assessed by determining dityrosine bond formation, which is indicated by the covalent coupling of the membrane-impermeable tyramine—fluorescein conjugate (TyrFluo) to HUVEC proteins. The acetylated membrane-permeable form of TyrFluo (acetylTyrFluo) was used for the determination of intracellular protein (ICP) oxidation. Oxidative stress was induced by exposing the HUVEC to PMA-activated human neutrophils, to a horseradish peroxidase/hydrogen peroxide (HRP/H2O2) system or to H2O2 alone. Coupling of the probes was determined by confocal laser scanning microscopy and by Western blotting using anti-fluorescein antibody. Diethylamine nitric oxide (DEANO) was used to determine the effect of NO on the tyrosyl radical formation in proteins. The oxidative burst generated by activated neutrophils for 15min, resulted in inducing dityrosine formation in ECP of HUVEC. Similar results were obtained with HRP/H2O2, but H2O2 alone did not have any effect on ECP. In the presence of DEANO (0.1mM or higher), ECP oxidation was almost completely inhibited. This indicates that NO may protect endothelial cells against protein oxidation by activated neutrophils under pro-inflammatory conditions. Activated neutrophils did not oxidize ICP of HUVEC, which strongly suggests that the effect of the oxidative burst was restricted to the proteins exposed to the medium.

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Gladstone, Igor M., e Rodney L. Levine. "Oxidation of Proteins in Neonatal Lungs". Pediatrics 93, n. 5 (1 maggio 1994): 764–68. http://dx.doi.org/10.1542/peds.93.5.764.

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Objective. To develop a method capable of quantifying the oxidative modification of proteins in pulmonary fluid obtained during routine suctioning of neonates receiving ventilation, thus providing an integrated assessment of antioxidant defenses. Design. Consecutive sample of neonates receiving ventilation. Setting. Neonatal intensive care unit. Patients. Twenty-six neonates receiving ventilation with a gestational age of 24 to 42 weeks, from whom 246 samples were collected and analyzed. Measurements and results. The carbonyl content in the lavage samples was measured by reaction with 2,4-dinitrophenylhydrazine followed by high-pressure liquid chromatography. Oxidation of proteins caused introduction of carbonyl groups into the side chains of the protein, providing a convenient and relatively specific marker of oxidative damage. On the first day of life, the initial protein-bound carbonyl for each neonate was usually low and consequently was not significantly related to birth weight, gestational age, or initial ventilatory requirements. Examination of the changes in pulmonary protein carbonyl in the first days of life revealed correlations of interest. In the first day of life, four neonates whose average inspired oxygen were <40% showed no increase in carbonyl content, whereas four neonates whose inspired oxygen was >40% showed an average increase in carbonyl of 51% (P < .001). Also, the need for ventilation >3 days was correlated with elevated carbonyl in those first 3 days. The carbonyl content averaged over the first 3 days was 0.13 ± 0.02 mol carbonyl/mol protein for the eight neonates receiving ventilation < 72 hours, whereas the nine needing longer ventilation had a carbonyl content of 0.28 ± 0.03 mol carbonyl/mol protein (P < .05). Seven neonates were treated with dexamethasone because of ventilator dependence at 14 days of age. In these neonates, treatment was associated with a 50% reduction in carbonyl content within 48 hours (P < .02). Conclusions. Oxidative damage to pulmonary proteins can be quantitated in samples obtained during routine suctioning of neonates receiving ventilation. The amount of oxidatively modified protein may provide a quantitative assessment of oxygen toxicity and of pulmonary antioxidant defenses.

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Chen, Chiao-nan, Deborah A. Ferrington e LaDora V. Thompson. "Carbonic anhydrase III and four-and-a-half LIM protein 1 are preferentially oxidized with muscle unloading". Journal of Applied Physiology 105, n. 5 (novembre 2008): 1554–61. http://dx.doi.org/10.1152/japplphysiol.90680.2008.

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The identities of proteins that show disuse-related changes in the content of oxidative modification are unknown. Furthermore, it is unknown whether the global accumulation of oxidized proteins is greater in aged animals with muscle disuse. The purposes of this study are 1) to identify the exact proteins that show disuse-related changes in oxidation levels and 2) to test the hypothesis that the global accumulation of oxidized proteins with muscle disuse would be greater in aged animals. Adult and old rats were randomized into four groups: weight bearing and 3, 7, or 14 days of hindlimb unloading. Soleus muscles were harvested to investigate the protein oxidation with unloading. Slot blot, SDS-PAGE, and Western blot analyses were used to detect the accumulation of 4-hydroxy-2-nonenol (HNE)- and nitrotyrosine (NT)-modified proteins. Matrix-assisted laser desorption ionization-time of flight and tandem mass spectroscopy were used to identify modified proteins. We found that global HNE- and NT-modified proteins accumulated significantly with aging but not with muscle unloading. Two HNE and NT target proteins, four-and-a-half LIM protein 1 (FHL1) and carbonic anhydrase III (CAIII), showed changes in the oxidation levels with muscle unloading. The changes in the oxidation levels happened to adult rats but not old rats. However, old rats had higher baseline levels of HNE-modified FHL1. In summary, the data suggest that the muscle unloading-related changes of protein oxidation are more significant in specific proteins and that the changes are age related.

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Quinlan, Roy A., e Philip J. Hogg. "γ-Crystallin redox–detox in the lens". Journal of Biological Chemistry 293, n. 46 (16 novembre 2018): 18010–11. http://dx.doi.org/10.1074/jbc.h118.006240.

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In the vertebrate eye, limiting oxidation of proteins and lipids is key to maintaining lens function and avoiding cataract formation. A study by Serebryany et al. identifies a surprising contributor to the eye's oxidative defense in their demonstration that γD-crystallin (HγD) functions as an oxidoreductase and uses disulfide exchange to initiate aggregation of mutant crystallins that mimic oxidative damage. These insights suggest a mechanism by which a dynamic pool of closely packed proteins might avoid oxidation-driven protein-folding traps, providing new avenues to understand the basis of a human disease with global impact.

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Eaton, P. "Reversible Cysteine-Targeted Oxidation of Proteins during Renal Oxidative Stress". Journal of the American Society of Nephrology 14, n. 90003 (1 agosto 2003): 290S—296. http://dx.doi.org/10.1097/01.asn.0000078024.50060.c6.

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Zheng, Kai, Diya Ren, Y. John Wang, Wayne Lilyestrom, Thomas Scherer, Justin K. Y. Hong e Junyan A. Ji. "Monoclonal Antibody Aggregation Associated with Free Radical Induced Oxidation". International Journal of Molecular Sciences 22, n. 8 (12 aprile 2021): 3952. http://dx.doi.org/10.3390/ijms22083952.

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Oxidation is an important degradation pathway of protein drugs. The susceptibility to oxidation is a common concern for therapeutic proteins as it may impact product efficacy and patient safety. In this work, we used 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH) as an oxidative stress reagent to evaluate the oxidation of therapeutic antibodies. In addition to the oxidation of methionine (Met) and tryptophan (Trp) residues, we also observed an increase of protein aggregation. Size-exclusion chromatography and multi-angle light scattering showed that the soluble aggregates induced by AAPH consist of dimer, tetramer, and higher-order aggregate species. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that inter-molecular disulfide bonds contributed to the protein aggregation. Furthermore, intrinsic fluorescence spectra suggested that dimerization of tyrosine (Tyr) residues could account for the non-reducible cross-links. An excipient screening study demonstrated that Trp, pyridoxine, or Tyr could effectively reduce protein aggregation due to oxidative stress. This work provides valuable insight into the mechanisms of oxidative-stress induced protein aggregation, as well as strategies to minimize such aggregate formation during the development and storage of therapeutic proteins.

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Li, Bowen, Ling Mo, Yuhui Yang, Shuai Zhang, Jingbing Xu, Yueting Ge, Yuncong Xu, Yonghui Shi e Guowei Le. "Processing milk causes the formation of protein oxidation products which impair spatial learning and memory in rats". RSC Advances 9, n. 39 (2019): 22161–75. http://dx.doi.org/10.1039/c9ra03223a.

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Eating a high protein oxidation diet leads to oxidative stress, leading to spatial learning and memory impairment. Dairy products processing conditions should be regulated to control the oxidation level of proteins, improve eating habits, and avoid damage to human health.

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Helander, Linda, Animesh Sharma, Hans E. Krokan, Kristjan Plaetzer, Barbara Krammer, Nicole Tortik, Odrun A. Gederaas, Geir Slupphaug e Lars Hagen. "Photodynamic treatment with hexyl-aminolevulinate mediates reversible thiol oxidation in core oxidative stress signaling proteins". Molecular BioSystems 12, n. 3 (2016): 796–805. http://dx.doi.org/10.1039/c5mb00744e.

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Stadtman, E. R., C. N. Oliver, P. E. Starke-Reed e S. G. Rhee. "Age-Related Oxidation Reaction in Proteins". Toxicology and Industrial Health 9, n. 1-2 (gennaio 1993): 187–96. http://dx.doi.org/10.1177/0748233793009001-213.

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Kim, Geumsoo, Stephen J. Weiss e Rodney L. Levine. "Methionine oxidation and reduction in proteins". Biochimica et Biophysica Acta (BBA) - General Subjects 1840, n. 2 (febbraio 2014): 901–5. http://dx.doi.org/10.1016/j.bbagen.2013.04.038.

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Haman, François, François Péronnet, Glen P. Kenny, Éric Doucet, Denis Massicotte, Carole Lavoie e Jean-Michel Weber. "Effects of carbohydrate availability on sustained shivering I. Oxidation of plasma glucose, muscle glycogen, and proteins". Journal of Applied Physiology 96, n. 1 (gennaio 2004): 32–40. http://dx.doi.org/10.1152/japplphysiol.00427.2003.

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Carbohydrates (CHO) can play an important thermogenic role during shivering, but the effect of their availability on the use of other oxidative fuels is unclear. Using indirect calorimetry and tracer methods ([U-13C]glucose ingestion), we have determined the specific contributions of plasma glucose, muscle glycogen, proteins, and lipids to total heat production (Ḣprod) in men exposed to cold for 2-h (liquid-conditioned suit perfused with 10°C water). Measurements were made after low-CHO diet and exercise (Lo) and high-CHO diet without exercise (Hi). The size of CHO reserves had no effect on Ḣprod but a major impact on fuel selection before and during shivering. In the cold, a complete shift from lipid oxidation for Lo (53, 28, and 19% Ḣprod for lipids, CHO, and proteins, respectively) to CHO-based metabolism for Hi (23, 65, and 12% Ḣprod for lipids, CHO, and proteins, respectively) was observed. Plasma glucose oxidation remains a minor fuel under all conditions (<13% Ḣprod), falling to 7% Ḣprod for Lo. Therefore, adjusting plasma glucose oxidation to compensate for changes in muscle glycogen oxidation is not a strategy used for maintaining heat production. Instead, proteins and lipids share responsibility for this compensation. We conclude that humans can show remarkable flexibility in oxidative fuel selection to ensure that heat production is not compromised during sustained cold exposure.

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Pietzsch, Jens, Ralf Bergmann e Steffi Kopprasch. "Analysis of non-protein amino acids as specific markers of low density lipoprotein apolipoprotein B-100 oxidation in human atherosclerotic lesions: the use ofN(O)-ethoxycarbonyl trifluoroethyl ester derivatives and GC-MS1". Spectroscopy 18, n. 2 (2004): 177–83. http://dx.doi.org/10.1155/2004/802375.

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Oxidative modification of proteins can interfere with critical cellular functions, and is widely regarded as a crucial event in the pathogenesis of various diseases ranging from rheumatoid arthritis to atherosclerosis and cancer. In this line, a new GC‒MS methodology usingN(O)‒ethoxycarbonyl trifluoroethyl amino acid esters (ECEE‒F3) for rapid and sensitive determination of 3‒chlorotyrosine, 5‒hydroxy‒2‒aminovaleric acid (HAVA), and 6‒hydroxy‒2‒aminocaproic acid (HACA) in proteins has been developed. 3‒Chlorotyrosine is a highly specific marker of myeloperoxidase catalyzed protein oxidation, whereas γ‒glutamyl semialdehyde (γGSA) and α‒aminoadipyl semialdehyde (αASA), which by reduction form HAVA and HACA, respectively, are specifically formed by metal catalyzed oxidation processes. ECEE‒F3derivatives are formed by the unlabored reaction of amino acids with ethylchloroformate plus trifluoroethanol plus pyridine. The key steps of the methodology employed are (i) enzymatic hydrolysis of target proteins to prevent decomposition of oxidation products during hydrolysis and (ii) an uniquely rapid derivatization of amino acids completing sample preparation for GC within a few minutes in aqueous solution at room temperature. The use of these stable products of protein amino acid side chain oxidation as potential markers for assessing oxidative damage in LDL apoB‒100 recovered from human aortic vascular lesions is demonstrated. These observations provide quantitative chemical evidence for metal catalyzed oxidative processes in the human artery wall.

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Raajendiran, Arthe, Christoph Krisp, David P. De Souza, Geraldine Ooi, Paul R. Burton, Renea A. Taylor, Mark P. Molloy e Matthew J. Watt. "Proteome analysis of human adipocytes identifies depot-specific heterogeneity at metabolic control points". American Journal of Physiology-Endocrinology and Metabolism 320, n. 6 (1 giugno 2021): E1068—E1084. http://dx.doi.org/10.1152/ajpendo.00473.2020.

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Adipocyte metabolism varies depending on anatomical location and the adipocyte protein composition may orchestrate this heterogeneity. We used SWATH proteomics in patient-matched human upper- (visceral and subcutaneous) and lower-body (glutealfemoral) adipocytes and detected 4,220 proteins and distinguishable regional proteomes. Upper-body adipocyte proteins were associated with glycolysis, de novo lipogenesis, mitochondrial dysfunction, and oxidative stress, whereas lower-body adipocyte proteins were associated with enhanced PPARα activation, fatty acid, and BCAA oxidation, TCA cycle flux, and oxidative phosphorylation.

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Krisko, Anita, e Miroslav Radman. "Protein damage, ageing and age-related diseases". Open Biology 9, n. 3 (marzo 2019): 180249. http://dx.doi.org/10.1098/rsob.180249.

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Ageing is considered as a snowballing phenotype of the accumulation of damaged dysfunctional or toxic proteins and silent mutations (polymorphisms) that sensitize relevant proteins to oxidative damage as inborn predispositions to age-related diseases. Ageing is not a disease, but it causes (or shares common cause with) age-related diseases as suggested by similar slopes of age-related increase in the incidence of diseases and death. Studies of robust and more standard species revealed that dysfunctional oxidatively damaged proteins are the root cause of radiation-induced morbidity and mortality. Oxidized proteins accumulate with age and cause reversible ageing-like phenotypes with some irreversible consequences (e.g. mutations). Here, we observe in yeast that aggregation rate of damaged proteins follows the Gompertz law of mortality and review arguments for a causal relationship between oxidative protein damage, ageing and disease. Aerobes evolved proteomes remarkably resistant to oxidative damage, but imperfectly folded proteins become sensitive to oxidation. We show that α-synuclein mutations that predispose to early-onset Parkinson's disease bestow an increased intrinsic sensitivity of α-synuclein to in vitro oxidation. Considering how initially silent protein polymorphism becomes phenotypic while causing age-related diseases and how protein damage leads to genome alterations inspires a vision of predictive diagnostic, prognostic, prevention and treatment of degenerative diseases.

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Tarrago, Lionel, Sandrine Grosse, David Lemaire, Laetitia Faure, Mathilde Tribout, Marina I. Siponen, Mila Kojadinovic-Sirinelli, David Pignol, Pascal Arnoux e Monique Sabaty. "Reduction of Protein Bound Methionine Sulfoxide by a Periplasmic Dimethyl Sulfoxide Reductase". Antioxidants 9, n. 7 (14 luglio 2020): 616. http://dx.doi.org/10.3390/antiox9070616.

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In proteins, methionine (Met) can be oxidized into Met sulfoxide (MetO). The ubiquitous methionine sulfoxide reductases (Msr) A and B are thiol-oxidoreductases reducing MetO. Reversible Met oxidation has a wide range of consequences, from protection against oxidative stress to fine-tuned regulation of protein functions. Bacteria distinguish themselves by the production of molybdenum-containing enzymes reducing MetO, such as the periplasmic MsrP which protects proteins during acute oxidative stress. The versatile dimethyl sulfoxide (DMSO) reductases were shown to reduce the free amino acid MetO, but their ability to reduce MetO within proteins was never evaluated. Here, using model oxidized proteins and peptides, enzymatic and mass spectrometry approaches, we showed that the Rhodobacter sphaeroides periplasmic DorA-type DMSO reductase reduces protein bound MetO as efficiently as the free amino acid L-MetO and with catalytic values in the range of those described for the canonical Msrs. The identification of this fourth type of enzyme able to reduce MetO in proteins, conserved across proteobacteria and actinobacteria, suggests that organisms employ enzymatic systems yet undiscovered to regulate protein oxidation states.

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Fischer, Manuel, Sebastian Horn, Anouar Belkacemi, Kerstin Kojer, Carmelina Petrungaro, Markus Habich, Muna Ali et al. "Protein import and oxidative folding in the mitochondrial intermembrane space of intact mammalian cells". Molecular Biology of the Cell 24, n. 14 (15 luglio 2013): 2160–70. http://dx.doi.org/10.1091/mbc.e12-12-0862.

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Oxidation of cysteine residues to disulfides drives import of many proteins into the intermembrane space of mitochondria. Recent studies in yeast unraveled the basic principles of mitochondrial protein oxidation, but the kinetics under physiological conditions is unknown. We developed assays to follow protein oxidation in living mammalian cells, which reveal that import and oxidative folding of proteins are kinetically and functionally coupled and depend on the oxidoreductase Mia40, the sulfhydryl oxidase augmenter of liver regeneration (ALR), and the intracellular glutathione pool. Kinetics of substrate oxidation depends on the amount of Mia40 and requires tightly balanced amounts of ALR. Mia40-dependent import of Cox19 in human cells depends on the inner membrane potential. Our observations reveal considerable differences in the velocities of mitochondrial import pathways: whereas preproteins with bipartite targeting sequences are imported within seconds, substrates of Mia40 remain in the cytosol for several minutes and apparently escape premature degradation and oxidation.

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Starke-Reed, Pamela E., Mark B. Reid, I. Tong Mak, Jay H. Kramer e William B. Weglicki. "Oxidation of cardiac cellular proteins and enzymes during acute oxidative stress". Free Radical Biology and Medicine 9 (gennaio 1990): 88. http://dx.doi.org/10.1016/0891-5849(90)90482-x.

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Tienson, Heather L., Deepa V. Dabir, Sonya E. Neal, Rachel Loo, Samuel A. Hasson, Pinmanee Boontheung, Sung-Kun Kim, Joseph A. Loo e Carla M. Koehler. "Reconstitution of the Mia40-Erv1 Oxidative Folding Pathway for the Small Tim Proteins". Molecular Biology of the Cell 20, n. 15 (agosto 2009): 3481–90. http://dx.doi.org/10.1091/mbc.e08-10-1062.

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Mia40 and Erv1 execute a disulfide relay to import the small Tim proteins into the mitochondrial intermembrane space. Here, we have reconstituted the oxidative folding pathway in vitro with Tim13 as a substrate and determined the midpoint potentials of Mia40 and Tim13. Specifically, Mia40 served as a direct oxidant of Tim13, and Erv1 was required to reoxidize Mia40. During oxidation, four electrons were transferred from Tim13 with the insertion of two disulfide bonds in succession. The extent of Tim13 oxidation was directly dependent on Mia40 concentration and independent of Erv1 concentration. Characterization of the midpoint potentials showed that electrons flowed from Tim13 with a more negative midpoint potential of −310 mV via Mia40 with an intermediate midpoint potential of −290 mV to the C130-C133 pair of Erv1 with a positive midpoint potential of −150 mV. Intermediary complexes between Tim13-Mia40 and Mia40-Erv1 were trapped. Last, mutating C133 of the catalytic C130-C133 pair or C30 of the shuttle C30-C33 pair in Erv1 abolished oxidation of Tim13, whereas mutating the cysteines in the redox-active CPC motif, but not the structural disulfide linkages of the CX9C motif of Mia40, prevented Tim13 oxidation. Thus, we demonstrate that Mia40, Erv1, and oxygen are the minimal machinery for Tim13 oxidation.

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Irokawa, Hayato, Satoshi Numasaki, Shin Kato, Kenta Iwai, Atsushi Inose-Maruyama, Takumi Ohdate, Gi-Wook Hwang, Takashi Toyama, Toshihiko Watanabe e Shusuke Kuge. "Comprehensive analyses of the cysteine thiol oxidation of PKM2 reveal the effects of multiple oxidation on cellular oxidative stress response". Biochemical Journal 478, n. 7 (16 aprile 2021): 1453–70. http://dx.doi.org/10.1042/bcj20200897.

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Redox regulation of proteins via cysteine residue oxidation is involved in the control of various cellular signal pathways. Pyruvate kinase M2 (PKM2), a rate-limiting enzyme in glycolysis, is critical for the metabolic shift from glycolysis to the pentose phosphate pathway under oxidative stress in cancer cell growth. The PKM2 tetramer is required for optimal pyruvate kinase (PK) activity, whereas the inhibition of inter-subunit interaction of PKM2 induced by Cys358 oxidation has reduced PK activity. In the present study, we identified three oxidation-sensitive cysteine residues (Cys358, Cys423 and Cys424) responsible for four oxidation forms via the thiol oxidant diamide and/or hydrogen peroxide (H2O2). Possibly due to obstruction of the dimer-dimer interface, H2O2-induced sulfenylation (-SOH) and diamide-induced modification at Cys424 inhibited tetramer formation and PK activity. Cys423 is responsible for intermolecular disulfide bonds with heterologous proteins via diamide. Additionally, intramolecular polysulphide linkage (–Sn–, n ≧ 3) between Cys358 and an unidentified PKM2 Cys could be induced by diamide. We observed that cells expressing the oxidation-resistant PKM2 (PKM2C358,424A) produced more intracellular reactive oxygen species (ROS) and exhibited greater sensitivity to ROS-generating reagents and ROS-inducible anti-cancer drugs compared with cells expressing wild-type PKM2. These results highlight the possibility that PKM2 inhibition via Cys358 and Cys424 oxidation contributes to eliminating excess ROS and oxidative stress.

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Mukthapura, Anita, Avinash Shimogga, Vinodchandran K, Beena Shetty e Gayathri Rao. "Oxidative Products of Proteins and Antioxidant Potential of Thiols in Gastric Carcinoma Patients". Journal of Medical Biochemistry 29, n. 2 (1 aprile 2010): 102–6. http://dx.doi.org/10.2478/v10011-010-0013-z.

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Oxidative Products of Proteins and Antioxidant Potential of Thiols in Gastric Carcinoma PatientsIt has been suggested that oxidative stress defined as a shift in antioxidant/oxidant balance towards oxidants is associated with the pathogenesis of many diseases, including carcinogenesis. Reactive oxygen species can induce carcinogenesis via injury to macromolecules such as DNA, carbohydrates and proteins. Forty primary gastric carcinoma patients and 40 healthy controls were included in the study. Advanced oxidation protein products, total thiols, total protein, albumin in plasma, % hemolysis in RBC suspension and glutathione in both whole blood and plasma were estimated. Our studies demonstrated a significant increase in advanced oxidation protein products, % hemolysis (p=0.033), A:G ratio (p=0.003) and a highly significant decrease in blood glutathione (p=0.036), total thiols (p=0.001), plasma thiols other than glutathione and total antioxidant activity. The findings suggest that gastric carcinoma is associated with oxygen derived free radicals accumulation, and depletion of total antioxidant activity has lead to oxidative stress and advancement of oxidative-antioxidative disorders followed by progression of gastric cancer.

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Maleknia, Simin D., e Kevin M. Downard. "Protein Footprinting with Radical Probe Mass Spectrometry- Two Decades of Achievement". Protein & Peptide Letters 26, n. 1 (13 febbraio 2019): 4–15. http://dx.doi.org/10.2174/0929866526666181128124241.

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Background: Radical Probe Mass Spectrometry (RP-MS) describes a pioneering methodology in structural biology that enables the study of protein structures, their interactions, and dynamics on fast timescales (down to sub-milliseconds). Hydroxyl radicals (•OH) generated directly from water within aqueous solutions induce the oxidation of reactive, solvent accessible amino acid side chains that are then analyzed by mass spectrometry. Introduced in 1998 at the American Society for Mass Spectrometry annual conference, RP-MS was first published on in 1999. Objective: This review article describes developments and applications of the RP-MS methodology over the past two decades. Methods: The RP-MS method has been variously referred to as synchrotron X-ray radiolysis footprinting, Hydroxyl Radical Protein Footprinting (HRPF), X-ray Footprinting with Mass Spectrometry (XF-MS), Fast Photochemical Oxidation of Proteins (FPOP), oxidative labelling, covalent oxidative labelling, and even the Stability of Proteins from Rates of Oxidation (SPROX). Results: The article describes the utility of hydroxyl radicals as a protein structural probe, the advantages of RP-MS in comparison to other MS-based approaches, its proof of concept using ion mobility mass spectrometry, its application to protein structure, folding, complex and aggregation studies, its extension to study the onset of protein damage, its implementation using a high throughput sample loading approach, and the development of protein docking algorithms to aid with data analysis and visualization. Conclusion: RP-MS represents a powerful new structural approach that can aid in our understanding of the structure and functions of proteins, and the impact of sustained oxidation on proteins in disease pathogenesis.

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Zergeroglu, Murat A., Michael J. McKenzie, R. Andrew Shanely, Darin Van Gammeren, Keith C. DeRuisseau e Scott K. Powers. "Mechanical ventilation-induced oxidative stress in the diaphragm". Journal of Applied Physiology 95, n. 3 (settembre 2003): 1116–24. http://dx.doi.org/10.1152/japplphysiol.00824.2002.

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Prolonged mechanical ventilation (MV) results in oxidative damage in the diaphragm; however, it is unclear whether this MV-induced oxidative injury occurs rapidly or develops slowly over time. Furthermore, it is unknown whether both soluble (cytosolic) and insoluble (myofibrillar) proteins are equally susceptible to oxidation during MV. These experiments tested two hypotheses: 1) MV-induced oxidative injury in the diaphragm occurs within the first 6 h after the initiation of MV; and 2) MV is associated with oxidative modification of both soluble and insoluble proteins. Adult Sprague-Dawley rats were randomly divided into one of seven experimental groups: 1) control ( n = 8); 2) 3-h MV ( n = 8); 3) 6-h MV ( n = 6); 4) 18-h MV ( n = 8); 5) 3-h anesthesia-spontaneous breathing ( n = 8); 6) 6-h anesthesia-spontaneous breathing ( n = 6); and 7) 18-h anesthesia-spontaneous breathing ( n = 8). Markers of oxidative injury in the diaphragm included the measurement of reactive (protein) carbonyl derivatives (RCD) and total lipid hydroperoxides. Three hours of MV did not result in oxidative injury in the diaphragm. In contrast, both 6 and 18 h of MV promoted oxidative injury in the diaphragm, as indicated by increases in both protein RCD and lipid hydroperoxides. Electrophoretic separation of soluble and insoluble proteins indicated that the MV-induced accumulation of RCD was limited to insoluble proteins with molecular masses of ∼200, 120, 80, and 40 kDa. We conclude that MV results in a rapid onset of oxidative injury in the diaphragm and that insoluble proteins are primary targets of MV-induced protein oxidation.

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33

Dick, Jeffrey M. "Average oxidation state of carbon in proteins". Journal of The Royal Society Interface 11, n. 100 (6 novembre 2014): 20131095. http://dx.doi.org/10.1098/rsif.2013.1095.

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The formal oxidation state of carbon atoms in organic molecules depends on the covalent structure. In proteins, the average oxidation state of carbon ( Z C ) can be calculated as an elemental ratio from the chemical formula. To investigate oxidation–reduction (redox) patterns, groups of proteins from different subcellular locations and phylogenetic groups were selected for comparison. Extracellular proteins of yeast have a relatively high oxidation state of carbon, corresponding with oxidizing conditions outside of the cell. However, an inverse relationship between Z C and redox potential occurs between the endoplasmic reticulum and cytoplasm. This trend provides support for the hypothesis that protein transport and turnover are ultimately coupled to the maintenance of different glutathione redox potentials in subcellular compartments. There are broad changes in Z C in whole-genome protein compositions in microbes from different environments, and in Rubisco homologues, lower Z C tends to occur in organisms with higher optimal growth temperature. Energetic costs calculated from thermodynamic models are consistent with the notion that thermophilic organisms exhibit molecular adaptation to not only high temperature but also the reducing nature of many hydrothermal fluids. Further characterization of the material requirements of protein metabolism in terms of the chemical conditions of cells and environments may help to reveal other linkages among biochemical processes with implications for changes on evolutionary time scales.

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Zhu, Xueshen, Zhenghao Ma, Xinyu Zhang, Xuefang Huang, Junya Liu e Xinbo Zhuang. "Effect of Malondialdehyde-Induced Oxidation Modification on Physicochemical Changes and Gel Characteristics of Duck Myofibrillar Proteins". Gels 8, n. 10 (6 ottobre 2022): 633. http://dx.doi.org/10.3390/gels8100633.

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This paper focuses on the effect of malondialdehyde-induced oxidative modification (MiOM) on the gel properties of duck myofibrillar proteins (DMPs). DMPs were first prepared and treated with oxidative modification at different concentrations of malondialdehyde (0, 0.5, 2.5, 5.0, and 10.0 mmol/L). The physicochemical changes (carbonyl content and free thiol content) and gel properties (gel whiteness, gel strength, water holding capacity, rheological properties, and microstructural properties) were then investigated. The results showed that the content of protein carbonyl content increased with increasing MDA oxidation (p < 0.05), while the free thiol content decreased significantly (p < 0.05). Meanwhile, there was a significant decrease in gel whiteness; the gel strength and water-holding capacity of protein gels increased significantly under a low oxidation concentration of MDA (0–5 mmol/L); however, the gel strength decreased under a high oxidation concentration (10 mmol/L) compared with other groups (0.5–5 mmol/L). The storage modulus and loss modulus of oxidized DMPs also increased with increasing concentrations at a low concentration of MDA (0–5 mmol/L); moreover, microstructural analysis confirmed that the gels oxidized at low concentrations (0.5–5 mmol/L) were more compact and homogeneous in terms of pore size compared to the high concentration or blank group. In conclusion, moderate oxidation of malondialdehyde was beneficial to improve the gel properties of duck; however, excessive oxidation was detrimental to the formation of dense structured gels.

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Márquez-Lázaro, Johana, Darío Méndez-Cuadro e Erika Rodríguez-Cavallo. "Residues of Fluoroquinolone Antibiotics Induce Carbonylation and Reduce In Vitro Digestion of Sarcoplasmic and Myofibrillar Beef Proteins". Foods 9, n. 2 (11 febbraio 2020): 170. http://dx.doi.org/10.3390/foods9020170.

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Although the impact of oxidation on human health has been of growing interest, the oxidation of proteins, major component of meat, has received little attention. This paper describes the in vitro effect of five fluoroquinolones (FQs) on carbonylation of sarcoplasmic and myofibrillar proteins of beef when found at concentrations close to the maximum residue limit (MRL). Samples were treated individually with the FQs, determining in each protein fraction the carbonyl index, protein content and oxidized proteins identification, using 2,4-dinitrophenyhydrazine (DNPH) alkaline assay, Western blot and Bradford methods, and mass spectrometry, respectively. Besides, the in vitro effect of these residues on gastric and duodenal digestion of proteins was evaluated. The carbonylation induced by FQs affected both protein fractions being significant with respect to the blank in 73.3% of cases. This damage was correlated with loss of solubility and digestibility, with sarcoplasmic proteins the most affected. Danofloxacin and enrofloxacin were the FQs with greatest oxidant effects, especially affecting glycolysis and glycogen proteins. Our results suggest that these residues induce irreversible oxidative damage on the main beef proteins and could affect their nutritional value.

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Perry, G., D. A. Zelasko, L. M. Sayre e M. A. Smith. "Oxidative Damage to Axonal Cytoskeletal Proteins". Microscopy and Microanalysis 3, S2 (agosto 1997): 43–44. http://dx.doi.org/10.1017/s1431927600007108.

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Proteins of the axonal cytoskeleton, particularly neurofilament and microtubule-associated protein τ, should be particularly sensitive to the effects of oxidative modification due to their high content of lysine, an amino acid that is particularly susceptible to direct oxidization as well as adduction by carbonyls produced from lipid and sugar oxidation. To understand the susceptibility of the cytoskeleton to oxidative modification and whether such modification is related to the physiological function of the cytoskeleton, we undertook a cytological analysis of motor neurons isolated from mouse spinal cord. These neurons contain an abundant axonal cytoskeleton that can be readily analyzed distinct from the cell body. Immunocytochemistry, using antibodies against protein-adducts of the highly reactive lipid peroxidation product, hydroxynonenal (HNE), representing Michael addition or pyrrole formation, revealed that HNE-immunoreactive adducts are found in all axons. This in situ distribution of HNE-adducts is consistent with immunoblots prepared from axons which show selective HNE modification of neurofilament heavy subunit (NFH) but not of other cytoskeletal proteins.

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37

Nlelsen, Henrik K., J. Löliger e R. F. Hurrell. "Reactions of proteins with oxidizing lipids". British Journal of Nutrition 53, n. 1 (gennaio 1985): 61–73. http://dx.doi.org/10.1079/bjn19850011.

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1. The reactions between protein-bound amino acids and oxidizing lipid were investigated in a whey protein-methyl linolenate (C18.3)–water model system. The extent of fat oxidation was followed by measuring oxygen uptake, hydroperoxide formation and hydrocarbon (ethane and pentane) formation.2. Significant losses occurred with lysine (up to 71 %), tryptophan (up to 31 %) and histidine (up to 57%). Methionine was extensively oxidized to its sulphoxide but less than 2% was further oxidized to the sulphone. No other amino acids were affected.3. Increasing storage temperature (20°, 37°, 55°) resulted in an enhancement of fat oxidation reactions and amino acid degradation.4. Increasing water activity (0.28, 0.65, 0.90) increased losses of lysine and tryptophan but had no influence on the oxidation of methionine, the level of remaining hydroperoxides or 02 uptake. Hydrocarbons were decreased.5. Limitation of 02 uptake to 1 mol/mol lipid instead of excess 02 (02 uptake about 2.5 mol/mol lipid in 4 weeks) significantly reduced the degradation of lysine and tryptophan but had less influence on the oxidation of methionine. The level of remaining hydroperoxides was increased but hydrocarbons were unaffected.

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Choromańska, Barbara, Piotr Myśliwiec, Tomasz Kozłowski, Magdalena Łuba, Piotr Wojskowicz, Jacek Dadan, Hanna Myśliwiec et al. "Antioxidant Barrier and Oxidative Damage to Proteins, Lipids, and DNA/RNA in Adrenal Tumor Patients". Oxidative Medicine and Cellular Longevity 2021 (22 giugno 2021): 1–19. http://dx.doi.org/10.1155/2021/5543531.

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This study is the first to assess redox balance, glutathione metabolism, and oxidative damage to RNA/DNA, proteins, and lipids in the plasma/serum and urine of patients with adrenal masses. The study included 70 patients with adrenal tumors divided into three subgroups: incidentaloma ( n = 30 ), pheochromocytoma ( n = 20 ), and Cushing’s/Conn’s adenoma ( n = 20 ), as well as 60 healthy controls. Blood and urine samples were collected before elective endoscopic adrenalectomy. Antioxidant defense capacity was significantly decreased (serum/plasma: superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH), uric acid (UA); urine: SOD, GSH, UA) in patients with adrenal masses. The oxidative damage to proteins (advanced glycation end products (AGE), advanced oxidation protein products (AOPP)) and lipids (lipid hydroperoxides (LOOH), and malondialdehyde (MDA)) was higher in the plasma and urine of these patients. Plasma MDA and DNA/RNA oxidation products, with high sensitivity and specificity, can help to diagnose pheochromocytoma. This biomarker differentiates patients with pheochromocytoma from Cushing’s/Conn’s adenoma as well as from heathy controls. Plasma RNA/DNA oxidation was also positively correlated with urine metanephrine. Oxidative stress can play a crucial role in adrenal tumors. However, further studies are required to clarify the role of redox signaling in adrenal masses.

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Yan, Liang-Jun. "Protein Redox Modification as a Cellular Defense Mechanism against Tissue Ischemic Injury". Oxidative Medicine and Cellular Longevity 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/343154.

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Abstract (sommario):

Protein oxidative or redox modifications induced by reactive oxygen species (ROS) or reactive nitrogen species (RNS) not only can impair protein function, but also can regulate and expand protein function under a variety of stressful conditions. Protein oxidative modifications can generally be classified into two categories: irreversible oxidation and reversible oxidation. While irreversible oxidation usually leads to protein aggregation and degradation, reversible oxidation that usually occurs on protein cysteine residues can often serve as an “on and off” switch that regulates protein function and redox signaling pathways upon stress challenges. In the context of ischemic tolerance, including preconditioning and postconditioning, increasing evidence has indicated that reversible cysteine redox modifications such as S-sulfonation, S-nitrosylation, S-glutathionylation, and disulfide bond formation can serve as a cellular defense mechanism against tissue ischemic injury. In this review, I highlight evidence of cysteine redox modifications as protective measures in ischemic injury, demonstrating that protein redox modifications can serve as a therapeutic target for attenuating tissue ischemic injury. Prospectively, more oxidatively modified proteins will need to be identified that can play protective roles in tissue ischemic injury, in particular, when the oxidative modifications of such identified proteins can be enhanced by pharmacological agents or drugs that are available or to be developed.

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Ngo, Vy, Nadun C. Karunatilleke, Anne Brickenden, Wing-Yiu Choy e Martin L. Duennwald. "Oxidative Stress-Induced Misfolding and Inclusion Formation of Nrf2 and Keap1". Antioxidants 11, n. 2 (27 gennaio 2022): 243. http://dx.doi.org/10.3390/antiox11020243.

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Cells that experience high levels of oxidative stress respond by inducing antioxidant proteins through activation of the protein transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). Nrf2 is negatively regulated by the E3 ubiquitin ligase Kelch-like ECH-associated protein 1 (Keap1), which binds to Nrf2 to facilitate its ubiquitination and ensuing proteasomal degradation under basal conditions. Here, we studied protein folding and misfolding in Nrf2 and Keap1 in yeast, mammalian cells, and purified proteins under oxidative stress conditions. Both Nrf2 and Keap1 are susceptible to protein misfolding and inclusion formation upon oxidative stress. We propose that the intrinsically disordered regions within Nrf2 and the high cysteine content of Keap1 contribute to their oxidation and the ensuing misfolding. Our work reveals previously unexplored aspects of Nrf2 and Keap1 regulation and/or dysregulation by oxidation-induced protein misfolding.

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Ortegón Salas, Clara, Katharina Schneider, Christopher Horst Lillig e Manuela Gellert. "Signal-regulated oxidation of proteins via MICAL". Biochemical Society Transactions 48, n. 2 (27 marzo 2020): 613–20. http://dx.doi.org/10.1042/bst20190866.

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Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

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Stadtman, E. R., e C. N. Oliver. "Metal-catalyzed oxidation of proteins. Physiological consequences". Journal of Biological Chemistry 266, n. 4 (febbraio 1991): 2005–8. http://dx.doi.org/10.1016/s0021-9258(18)52199-2.

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Nacak, B., H. S. Kavuşan e M. Serdaroğlu. "Effect of α-tocopherol, rosemary extract and their combination on lipid and protein oxidation in beef sausages". IOP Conference Series: Earth and Environmental Science 854, n. 1 (1 ottobre 2021): 012062. http://dx.doi.org/10.1088/1755-1315/854/1/012062.

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Abstract This study focuses on the oxidative changes in lipids and proteins of beef sausages with incorporated a-tocopherol, rosemary extract or their combination during 3 months’ storage at 4°C. For this purpose, sausages were formulated with no antioxidant (Control, C), 200 ppm a-tocopherol (T), 200 ppm rosemary extract (R), and 100 ppm a-tocopherol + 100 ppm rosemary extract (TR). To observe oxidative changes in lipids; peroxide value, thiobarbituric acid reactive substances (TBARS), and total oxidation value (TOTOX), in proteins; sulfhydryl and carbonyl contents were measured. Use of antioxidants and storage time significantly affected oxidative stability of sausages (P<0.05). Antioxidants, individually or in combination, retarded lipid peroxidation and improve the oxidative stability of sausage during storage. The antioxidant combination showed synergistic effect on protein oxidation, as the lowest carbonyl contents were found in TR samples. As a result, a combination of antioxidants with different effect mechanisms could be the better option to prevent oxidative changes in meat products.

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Sumner, Edward R., Anupama Shanmuganathan, Theodora C. Sideri, Sylvia A. Willetts, John E. Houghton e Simon V. Avery. "Oxidative protein damage causes chromium toxicity in yeast". Microbiology 151, n. 6 (1 giugno 2005): 1939–48. http://dx.doi.org/10.1099/mic.0.27945-0.

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Oxidative damage in microbial cells occurs during exposure to the toxic metal chromium, but it is not certain whether such oxidation accounts for the toxicity of Cr. Here, a Saccharomyces cerevisiae sod1Δ mutant (defective for the Cu,Zn-superoxide dismutase) was found to be hypersensitive to Cr(VI) toxicity under aerobic conditions, but this phenotype was suppressed under anaerobic conditions. Studies with cells expressing a Sod1p variant (Sod1H46C) showed that the superoxide dismutase activity rather than the metal-binding function of Sod1p was required for Cr resistance. To help identify the macromolecular target(s) of Cr-dependent oxidative damage, cells deficient for the reduction of phospholipid hydroperoxides (gpx3Δ and gpx1Δ/gpx2Δ/gpx3Δ) and for the repair of DNA oxidation (ogg1Δ and rad30Δ/ogg1Δ) were tested, but were found not to be Cr-sensitive. In contrast, S. cerevisiae msraΔ (mxr1Δ) and msrbΔ (ycl033cΔ) mutants defective for peptide methionine sulfoxide reductase (MSR) activity exhibited a Cr sensitivity phenotype, and cells overexpressing these enzymes were Cr-resistant. Overexpression of MSRs also suppressed the Cr sensitivity of sod1Δ cells. The inference that protein oxidation is a primary mechanism of Cr toxicity was corroborated by an observed ∼20-fold increase in the cellular levels of protein carbonyls within 30 min of Cr exposure. Carbonylation was not distributed evenly among the expressed proteins of the cells; certain glycolytic enzymes and heat-shock proteins were specifically targeted by Cr-dependent oxidative damage. This study establishes an oxidative mode of Cr toxicity in S. cerevisiae, which primarily involves oxidative damage to cellular proteins.

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Alvarado, Gerardo, Attila Tóth, Éva Csősz, Gergő Kalló, Katalin Dankó, Zoltán Csernátony, Ann Smith et al. "Heme-Induced Oxidation of Cysteine Groups of Myofilament Proteins Leads to Contractile Dysfunction of Permeabilized Human Skeletal Muscle Fibres". International Journal of Molecular Sciences 21, n. 21 (31 ottobre 2020): 8172. http://dx.doi.org/10.3390/ijms21218172.

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Heme released from red blood cells targets a number of cell components including the cytoskeleton. The purpose of the present study was to determine the impact of free heme (20–300 µM) on human skeletal muscle fibres made available during orthopedic surgery. Isometric force production and oxidative protein modifications were monitored in permeabilized skeletal muscle fibre segments. A single heme exposure (20 µM) to muscle fibres decreased Ca2+-activated maximal (active) force (Fo) by about 50% and evoked an approximately 3-fold increase in Ca2+-independent (passive) force (Fpassive). Oxidation of sulfhydryl (SH) groups was detected in structural proteins (e.g., nebulin, α-actinin, meromyosin 2) and in contractile proteins (e.g., myosin heavy chain and myosin-binding protein C) as well as in titin in the presence of 300 µM heme. This SH oxidation was not reversed by dithiothreitol (50 mM). Sulfenic acid (SOH) formation was also detected in the structural proteins (nebulin, α-actinin, meromyosin). Heme effects on SH oxidation and SOH formation were prevented by hemopexin (Hpx) and α1-microglobulin (A1M). These data suggest that free heme has a significant impact on human skeletal muscle fibres, whereby oxidative alterations in structural and contractile proteins limit contractile function. This may explain and or contribute to the weakness and increase of skeletal muscle stiffness in chronic heart failure, rhabdomyolysis, and other hemolytic diseases. Therefore, therapeutic use of Hpx and A1M supplementation might be effective in preventing heme-induced skeletal muscle alterations.

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Kiffin, Roberta, Christopher Christian, Erwin Knecht e Ana Maria Cuervo. "Activation of Chaperone-mediated Autophagy during Oxidative Stress". Molecular Biology of the Cell 15, n. 11 (novembre 2004): 4829–40. http://dx.doi.org/10.1091/mbc.e04-06-0477.

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Oxidatively damaged proteins accumulate with age in almost all cell types and tissues. The activity of chaperone-mediated autophagy (CMA), a selective pathway for the degradation of cytosolic proteins in lysosomes, decreases with age. We have analyzed the possible participation of CMA in the removal of oxidized proteins in rat liver and cultured mouse fibroblasts. Added to the fact that CMA substrates, when oxidized, are more efficiently internalized into lysosomes, we have found a constitutive activation of CMA during oxidative stress. Oxidation-induced activation of CMA correlates with higher levels of several components of the lysosomal translocation complex, but in particular of the lumenal chaperone, required for substrate uptake, and of the lysosomal membrane protein (lamp) type 2a, previously identified as a receptor for this pathway. In contrast with the well characterized mechanism of CMA activation during nutritional stress, which does not require de novo synthesis of the receptor, oxidation-induced activation of CMA is attained through transcriptional up-regulation of lamp2a. We conclude that CMA is activated during oxidative stress and that the higher activity of this pathway under these conditions, along with the higher susceptibility of the oxidized proteins to be taken up by lysosomes, both contribute to the efficient removal of oxidized proteins.

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Hopps, Eugenia, e Gregorio Caimi. "Protein Oxidation in Metabolic Syndrome". Clinical & Investigative Medicine 36, n. 1 (1 febbraio 2013): 1. http://dx.doi.org/10.25011/cim.v36i1.19399.

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Abstract (sommario):

Purpose: Oxidative stress plays a pivotal role in the pathogenesis of the metabolic syndrome and in the progression of its complications. Carbonylated proteins are a stable marker of severe oxidative stress because damage to the protein structure is irreversible and may cause an inhibition of their enzymatic activity or an increased susceptibility to proteolysis. There are few data regarding protein oxidation in metabolic syndrome, although elevated levels of carbonyl groups are often detected in subjects with obesity, diabetes mellitus, hypertension or dyslipidemia, well-known components of the metaboic syndrome. In particular, obesity, insulin resistance and diabetes mellitus are frequently associated with increased protein carbonylation. A relationship between insulin resistance, protein oxidative stress and inflammation has also been suggested as well as protein oxidation products are correlated with overexpression of resistin, TNF-α and IL-6. Conclusion: Therapeutic interventions based on lifestyle modifications and pharmacological agents in order to correct all the main risk factors influence oxidative stress and protein carbonylation.

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Umstead, Todd M., Willard M. Freeman, Vernon M. Chinchilli e David S. Phelps. "Age-related changes in the expression and oxidation of bronchoalveolar lavage proteins in the rat". American Journal of Physiology-Lung Cellular and Molecular Physiology 296, n. 1 (gennaio 2009): L14—L29. http://dx.doi.org/10.1152/ajplung.90366.2008.

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The incidence and severity of many lung diseases change with age. Some diseases, such as pneumonia, occur with increased frequency in children and the elderly. Proteins obtained by bronchoalveolar lavage (BAL) serve as the first line of defense against inhaled toxins and pathogens. Age-related changes in BAL protein expression and oxidative modification were examined in juvenile (1 mo), young adult (2 mo), and aged (18 mo) F344 rats using two-dimensional difference gel electrophoresis (2D-DIGE), matrix-assisted laser desorption ionization-time of flight/time of flight (MALDI-ToF/ToF) tandem mass spectrometry, and carbonyl immunoblotting. Using 2D-DIGE, we detected 563 protein spots, and MALDI-ToF/ToF identified 204 spots comprising 31 proteins; 21 changed significantly (17 increases) between juvenile and young adult or aged rats, but for 12 of these proteins, levels had a biphasic pattern, and levels in aged rats were less than in young adults. Relative carbonylation was determined by comparison of immunostaining with total protein staining on each oxidized protein blot. We found that aged rats had significantly increased oxidation in 13 proteins compared with juvenile rats. Many of the proteins altered in expression or oxidation level had functions in host defense, redox regulation, and protein metabolism. We speculate that low levels of expression of host defense proteins in juvenile rats and decreases in levels of these proteins between young adult and aged rats may predispose these groups to pneumonia. In addition, we have shown age-related increases in protein oxidation that may compromise host defense function in aged rats.

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Shaw, C. S., C. Swinton, M. G. Morales-Scholz, N. McRae, T. Erftemeyer, A. Aldous, R. M. Murphy e K. F. Howlett. "Impact of exercise training status on the fiber type-specific abundance of proteins regulating intramuscular lipid metabolism". Journal of Applied Physiology 128, n. 2 (1 febbraio 2020): 379–89. http://dx.doi.org/10.1152/japplphysiol.00797.2019.

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Endurance training enhances the capacity for fat oxidation during exercise due to increased utilization of intramuscular lipid (IMCL). This study quantitatively investigated the impact of exercise training status on muscle fiber type-specific abundance of regulatory proteins involved in IMCL utilization. Endurance-trained [ n = 7 subjects, peak oxygen consumption (V̇o2peak) 62.6 ± 4.1 (SD) mL·min−1·kg−1] and non-endurance-trained ( n = 8 subjects, V̇o2peak 44.9 ± 5.3 mL·min−1·kg−1) young men completed an incremental exercise test to determine maximal fat oxidation (MFO) and maximal oxygen uptake. Fiber type-specific IMCL content and protein abundance were assessed with immunofluorescence microscopy and immunoblot analysis of pooled single muscle fibers and whole muscle. Endurance-trained individuals displayed a higher MFO rate (0.45 ± 0.15 vs. 0.19 ± 0.07 g/min, P < 0.05), a greater proportion of type I muscle fibers, and higher IMCL content compared with untrained individuals ( P < 0.05). Adipose triglyceride lipase, hormone-sensitive lipase, perilipin 2, perilipin 5, and hydroxyacyl-coenzyme A dehydrogenase abundances were ~2–3-fold higher in type I muscle fibers compared with type IIa fibers ( P < 0.05). Correspondingly, these lipid proteins and oxidative enzymes were higher in endurance-trained individuals when assessed in whole muscle. MFO rate was strongly related to the proportion of type I fibers ( R = 0.81, P < 0.01). The abundance of proteins involved in the regulation of IMCL storage and oxidation is highly muscle fiber type specific. The increased capacity for fat oxidation in endurance-trained individuals corresponded with increased IMCL content and elevated abundance of lipolytic and oxidative enzymes in combination with a greater proportion of type I muscle fibers. NEW & NOTEWORTHY We have utilized contemporary techniques to compare the fiber type-specific characteristics of skeletal muscle from endurance-trained athletes and untrained individuals. We show that type I muscle fibers have a coordinated upregulation of proteins controlling intramuscular lipid storage, mobilization, and oxidation. Furthermore, the enhanced capacity for intramuscular lipid storage and utilization in endurance-trained individuals is related to the increased expression of lipid regulatory proteins combined with a greater proportion of type I muscle fibers.

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Gebicki, J. M., J. Du, J. Collins e H. Tweeddale. "Peroxidation of proteins and lipids in suspensions of liposomes, in blood serum, and in mouse myeloma cells." Acta Biochimica Polonica 47, n. 4 (31 dicembre 2000): 901–11. http://dx.doi.org/10.18388/abp.2000_3945.

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There is growing evidence that proteins are early targets of reactive oxygen species, and that the altered proteins can in turn damage other biomolecules. In this study, we measured the effects of proteins on the oxidation of liposome phospholipid membranes, and the formation of protein hydroperoxides in serum and in cultured cells exposed to radiation-generated hydroxyl free radicals. Lysozyme, which did not affect liposome stability, gave 50% protection when present at 0.3 mg/ml, and virtually completely prevented lipid oxidation at 10 mg/ml. When human blood serum was irradiated, lipids were oxidized only after the destruction of ascorbate. In contrast, peroxidation of proteins proceeded immediately. Protein hydroperoxides were also generated without a lag period in hybrid mouse myeloma cells, while at the same time no lipid peroxides formed. These results are consistent with the theory that, under physiological conditions, lipid membranes are likely to be effectively protected from randomly-generated hydroxyl radicals by proteins, and that protein peroxyl radicals and hydroperoxides may constitute an important hazard to biological systems under oxidative stress.

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