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Loubane G, Robert G, Firdaus SB, Venne P, Comeau C, Boudreault PL, Komba JE, Wagner JR, Naylor S, Klarskov K. Conundrum of dehydroascorbic acid and homocysteine thiolactone reaction products: Structural characterization and effect on peptide and protein N-homocysteinylation. Free Radic Biol Med 2023; 206:111-124. [PMID: 37385568 DOI: 10.1016/j.freeradbiomed.2023.06.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/16/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
An excessive blood level of homocysteine (HcySH) is associated with numerous cardiovascular and neurodegenerative disease conditions. It has been suggested that direct S-homocysteinylation, of proteins by HcySH, or N-homosteinylation by homocysteine thiolactone (HTL) could play a causative role in these maladies. In contrast, ascorbic acid (AA) plays a significant role in oxidative stress prevention. AA is oxidized to dehydroascorbic acid (DHA) and if not rapidly reduced back to AA may degrade to reactive carbonyl products. In the present work, DHA is shown to react with HTL to produce a spiro bicyclic ring containing a six-membered thiazinane-carboxylic acid moiety. This reaction product is likely formed by initial imine condensation and subsequent hemiaminal product followed by HTL ring opening and intramolecular nucleophilic attack of the resulting thiol anion to form the spiro product. The reaction product was determined to have an accurate mass of 291.0414 and a molecular composition C10H13NO7S containing five double bond equivalents. We structurally characterized the reaction product using a combination of accurate mass tandem mass spectrometry, 1D and 2D-nuclear magnetic resonance. We also demonstrated that formation of the reaction product prevented peptide and protein N-homocysteinylation by HTL using a model peptide and α-lactalbumin. Furthermore, the reaction product is formed in Jurkat cells when exposed to HTL and DHA.
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Affiliation(s)
- Ghizlane Loubane
- Département de Pharmacologie et Physiologie Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA
| | - Gabriel Robert
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA
| | - Syed Benazir Firdaus
- Département de Pharmacologie et Physiologie Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA
| | - Philippe Venne
- Département de Chimie, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA
| | - Christian Comeau
- Département de Chimie, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA
| | | | - Jeampy E Komba
- Département de Pharmacologie et Physiologie Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA
| | - J Richard Wagner
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA
| | - Stephen Naylor
- ReNeuroGen LLC, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA
| | - Klaus Klarskov
- Département de Pharmacologie et Physiologie Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 2160 San Fernando Drive, Milwaukee, WI, 53122, USA.
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Tatzber F, Zelzer S, Obermayer-Pietsch B, Rinnerhofer S, Kundi M, Cvirn G, Wultsch G, Herrmann M, Mangge H, Niedrist T, Wonisch W. Occupational Health Aspects with Special Focus on Physiological Differences between Office and Metalworkers. Antioxidants (Basel) 2022; 11:antiox11040633. [PMID: 35453318 PMCID: PMC9032298 DOI: 10.3390/antiox11040633] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 02/07/2023] Open
Abstract
Physical workload adversely impacts inflammation, oxidative stress and mood in heavy workers. We compared these risk parameters between metalworkers (n = 20) and office workers (n = 30), including gender differences. Blood samples were analyzed with thirty parameters to overview endocrinology, inflammation, and psychological and oxidative stress. Despite an adequate antioxidative supply, oxidative stress occurred in metalworkers, as indicated by significantly increased peroxide and homocysteine (Hcy) levels. Moreover, increased concentrations were observed in this group regarding psychological stress and diet-related parameters. Sex-specific differences were determined for physical dimensions, dehydroepiandrosterone sulfate (DHEAS), Hcy, uric acid, triglycerides, osmolality, anti-Mullerian hormone (AMH) and testosterone. Age-associated differences were observed for DHEAS, glycosylated hemoglobin, adrenaline, AMH and testosterone. In male office workers, the body mass index was associated with increased LDL-HDL, cholesterol-HDL and homeostatic model assessment of insulin resistance (HOMA-IR). In conclusion, these results indicate increased oxidative stress and psychological stress in heavy workers independently of adequate antioxidant sustenance. The sedentary occupation of office workers, in turn, favored diseases of affluence. This might be particularly relevant for long-term occupied persons and older workers due to a hormonal shift coming along, given the risk for oxidative stress-related diseases such as cardiovascular disease, particularly in the case of males, based on their lifestyle habits.
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Affiliation(s)
- Franz Tatzber
- Otto Loewi Research Center, Division of Immunology and Pathophysiology, Medical University of Graz, Heinrichstraße 31a, 8010 Graz, Austria;
| | - Sieglinde Zelzer
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria; (S.Z.); (M.H.); (H.M.); (T.N.)
| | - Barbara Obermayer-Pietsch
- Endocrinology Lab Platform, Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria;
| | - Stefan Rinnerhofer
- Exercise Physiology, Training and Training Therapy Research Group, Institute of Sports Science, University of Graz, Mozartgasse 14, 8010 Graz, Austria;
| | - Michael Kundi
- Center for Public Health, Department of Environmental Health, Medical University of Vienna, Kinderspitalgasse 15, 1090 Vienna, Austria;
| | - Gerhard Cvirn
- Otto Loewi Research Center, Division of Physiological Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6 HBK M1/D3, 8010 Graz, Austria;
| | - Georg Wultsch
- Arbeitsmedizinisches Institut Graz, Herrgottwiesgasse 149, 8055 Graz, Austria;
| | - Markus Herrmann
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria; (S.Z.); (M.H.); (H.M.); (T.N.)
| | - Harald Mangge
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria; (S.Z.); (M.H.); (H.M.); (T.N.)
| | - Tobias Niedrist
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria; (S.Z.); (M.H.); (H.M.); (T.N.)
| | - Willibald Wonisch
- Otto Loewi Research Center, Division of Physiological Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6 HBK M1/D3, 8010 Graz, Austria;
- Correspondence: ; Tel.: +43-650-52-99-540
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Poljsak B, Kovač V, Milisav I. Antioxidants, Food Processing and Health. Antioxidants (Basel) 2021; 10:antiox10030433. [PMID: 33799844 PMCID: PMC8001021 DOI: 10.3390/antiox10030433] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 11/29/2022] Open
Abstract
The loss and/or modification of natural antioxidants during various food processing techniques and storage methods, like heat/thermal, UV, pulsed electric field treatment, drying, blanching and irradiation is well described. Antioxidants in their reduced form are modified mainly by oxidation, and less by pyrolysis and hydrolysis. Thus, they are chemically converted from the reduced to an oxidized form. Here we describe the neglected role of the oxidized forms of antioxidants produced during food processing and their effect on health. While natural antioxidants in their reduced forms have many well studied health-promoting characteristics, much less is known about the effects of their oxidized forms and other metabolites, which may have some health benefits as well. The oxidized forms of natural antioxidants affect cell signaling, the regulation of transcription factor activities and other determinants of gene expression. Very low doses may trigger hormesis, resulting in specific health benefits by the activation of damage repair processes and antioxidative defense systems. Functional studies determining the antioxidants’ effects on the organisms are important, especially as reduced or oxidized antioxidants and their metabolites may have additional or synergistic effects.
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Affiliation(s)
- Borut Poljsak
- Laboratory of Oxidative Stress Research, Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenia; (B.P.); (V.K.)
| | - Vito Kovač
- Laboratory of Oxidative Stress Research, Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenia; (B.P.); (V.K.)
| | - Irina Milisav
- Laboratory of Oxidative Stress Research, Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenia; (B.P.); (V.K.)
- Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
- Correspondence: ; Tel.: +386-1-543-7022; Fax: +386-1-543-7021
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Cerit İ, Pfaff A, Ercal N, Demirkol O. Postharvest application of thiol compounds affects surface browning and antioxidant activity of fresh-cut potatoes. J Food Biochem 2020; 44:e13378. [PMID: 32729123 DOI: 10.1111/jfbc.13378] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/14/2020] [Accepted: 06/25/2020] [Indexed: 12/01/2022]
Abstract
The aim of this study was to compare the effects of sodium metabisulphite and the thiol compounds, glutathione (GSH), L-cysteine (CYS), and N-acetylcysteine (NAC), on the enzymatic browning, antioxidant activities, total phenolic, and ascorbic acid content of potatoes after 1, 24, and 48 hr. Three different concentrations (0.5%, 1.0%, and 2.0%) of each thiol compound were tested. While sulphite solution inhibited polyphenol oxidase as expected, NAC and CYS also decreased its activity. CYS-treated samples exhibited the highest residual thiol content, while the amount of residual thiol in GSH-treated samples was the lowest. The 2.0% NAC and 2.0% CYS solutions were the most effective at increasing antioxidant activity and ascorbic acid content; however, the results of total phenolic content assays were complicated. In summary, solutions containing 2.0% NAC, 1.0% CYS, and 2.0% CYS prevented enzymatic browning and increased the residual thiol content, ascorbic acid, and antioxidant activities of fresh-cut potatoes significantly, but GSH did not significantly inhibit browning. PRACTICAL APPLICATIONS: Fresh-cut potatoes are susceptible to enzymatic browning, which significantly reduces their commercial value. In literature, there have been several methods to protect the enzymatic browning of fruits and vegetables. Among these methods, thiols are good inhibitors of enzymatic browning. So, GSH, CYS, and NAC were used in this study. The outcomes of current work may help to inhibit polyphenol oxidase activity and increase the ascorbic acid content, residual thiol content, and antioxidant activity of fresh-cut potatoes. Both CYS and NAC may be useful alternatives to sulphite anti-browning agents, which may have adverse health effects.
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Affiliation(s)
- İnci Cerit
- Faculty of Engineering, Department of Food Engineering, Sakarya University, Sakarya, Turkey
| | - Annalise Pfaff
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO, USA
| | - Nuran Ercal
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO, USA
| | - Omca Demirkol
- Faculty of Engineering, Department of Food Engineering, Sakarya University, Sakarya, Turkey
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Ahuie GK, Gagnon H, Pace PE, Peskin AV, Wagner RJ, Naylor S, Klarskov K. Investigating protein thiol chemistry associated with dehydroascorbate, homocysteine and glutathione using mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8774. [PMID: 32119756 DOI: 10.1002/rcm.8774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 01/05/2020] [Accepted: 02/23/2020] [Indexed: 06/10/2023]
Abstract
RATIONALE Oxidative stress is an imbalance between reactive free radical oxygen species and antioxidant defenses. Its consequences can lead to numerous pathologies. Regulating oxidative stress is the complex interplay between antioxidant recycling and thiol-containing regulatory proteins. Understanding these regulatory mechanisms is important for preventing onset of oxidative stress. The aim of this study was to investigae S-thiol protein chemistry associated with oxidized vitamin C (dehydroascorbate, DHA), homocysteine (HcySH) and glutathione (GSH) using mass spectrometry. METHODS Glutaredoxin-1 (Grx-1) was incubated with DHA, with and without GSH and HcySH. Disulfide formation was followed by electrospray ionization mass spectrometry (ESI-MS) of intact proteins and by LC/ESI-MS/MS of peptides from protein tryptic digestions. The mechanism of DHA-mediated S-thiolation was investigated using two synthetic peptides: AcFHACAAK and AcFHACE. Three proteins, i.e. human hemoglobin (HHb), recombinant peroxiredoxin 2 (Prdx2) and Grx-1, were S-homocysteinylated followed by S-transthiolyation with GSH and investigated by ESI-MS and ESI-MS/MS. RESULTS ESI-MS analysis reveals that DHA mediates disulfide formation and S-thiolation by HcySH as well as GSH of Grx-1. LC/ESI-MS/MS analysis allows identification of Grx-1 S-thiolated cysteine adducts. The mechanism by which DHA mediates S-thiolation of heptapeptide AcFHACAAK is shown to be via initial formation of a thiohemiketal adduct. In addition, ESI-MS of intact proteins shows that GSH can S-transthiolate S-homocysteinylated Grx-1_ HHb and Prdx2. The GS-S-protein adducts over time dominate the ESI-MS spectrum profile. CONCLUSIONS Mass spectrometry is a unique analytical technique for probing complex reaction mechanisms associated with oxidative stress. Using model proteins, ESI-MS reveals the mechanism of DHA-facilitated S-thiolation, which consists of thiohemiketal formation, disulfide formation or S-thiolation. Furthermore, protein S-thiolation by HcySH can be reversed by reversible GSH thiol exchange. The use of mass spectrometry with in vitro models of protein S-thiolation in oxidative stress may provide significant insight into possible mechanisms of action occurring in vivo.
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Affiliation(s)
- Grace Kouakou Ahuie
- Département de Pharmacologie et Physiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001 Avenue Nord, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Hugo Gagnon
- PhenoSwitch Bioscience, 975 Rue Léon-Trépanier, Sherbrooke, Quebec, J1G 5J6, Canada
| | - Paul E Pace
- Centre for Free Radical Research, University of Otago Christchurch, 2 Riccarton Avenue, Christchurch, 8140, New Zealand
| | - Alexander V Peskin
- Centre for Free Radical Research, University of Otago Christchurch, 2 Riccarton Avenue, Christchurch, 8140, New Zealand
| | - Richard J Wagner
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001 Avenue Nord, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Stephen Naylor
- ReNeuroGen LLC, 2160 San Fernando Drive, Elm Grove, WI, 53122, USA
| | - Klaus Klarskov
- Département de Pharmacologie et Physiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001 Avenue Nord, Sherbrooke, Quebec, J1H 5N4, Canada
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6
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Vitamin C loss kinetics and shelf life study in fruit-based baby foods during post packaging storage. Food Packag Shelf Life 2020. [DOI: 10.1016/j.fpsl.2019.100453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Ahuié Kouakou G, Gagnon H, Lacasse V, Wagner JR, Naylor S, Klarskov K. Dehydroascorbic acid S-Thiolation of peptides and proteins: Role of homocysteine and glutathione. Free Radic Biol Med 2019; 141:233-243. [PMID: 31228548 DOI: 10.1016/j.freeradbiomed.2019.06.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/13/2019] [Accepted: 06/17/2019] [Indexed: 01/05/2023]
Abstract
Ascorbic acid (vitamin C) plays a significant role in the prevention of oxidative stress. In this process, ascorbate is oxidized to dehydroascorbate (DHA). We have investigated the impact of DHA on peptide/protein intramolecular disulfide formation as well as S-glutathionylation and S-homocysteinylation. S-glutathionylation of peptides/proteins is a reversible, potential regulatory mechanism in oxidative stress. Although the exact role of protein S-homocysteinylation is unknown, it has been proposed to be of importance in pathobiological processes such as onset of cardiovascular disease. Using an in vitro model system, we demonstrate that DHA causes disulfide bond formation within the active site of recombinant human glutaredoxin (Grx-1). DHA also facilities the formation of S-glutathionylation and S-homocysteinylation of a model peptide (AcFHACAAK) as well as Grx-1. We discuss the possible mechanisms of peptide/protein S-thiolation, which can occur either via thiol exchange or a thiohemiketal intermediate. A thiohemiketal DHA-peptide adduct was detected by mass spectrometry and its location on the peptide/protein cysteinyl thiol group was unambiguously confirmed by tandem mass spectrometry. This demonstrates that peptide/protein S-thiolation mediated by DHA is not limited to thiol exchange reactions but also takes place directly via the formation of a thiohemiketal peptide intermediate. Finally, we investigated a potential reducing role of glutathione (GSH) in the presence of S-homocysteinylated peptide/protein adducts. S-homocysteinylated AcFHACAAK, human hemoglobin α-chain and Grx-1 were incubated with GSH. Both peptide and proteins were reduced, and homocysteine replaced with GS-adducts by thiol exchange, as a function of time.
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Affiliation(s)
- Grace Ahuié Kouakou
- Département de Pharmacologie et Physiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Canada
| | - Hugo Gagnon
- PhenoSwitch Bioscience, 975 Rue Léon-Trépanier, Sherbrooke, QC J1G 5J6, Canada
| | - Vincent Lacasse
- Département de Pharmacologie et Physiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Canada
| | - J Richard Wagner
- Département de Médecine Nucléaire et radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Canada
| | - Stephen Naylor
- ReNeuroGen LLC, 2160 San Fernando Drive, Elm Grove, WI, 53122, USA
| | - Klaus Klarskov
- Département de Pharmacologie et Physiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Canada.
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Borowczyk K, Suliburska J, Jakubowski H. Demethylation of methionine and keratin damage in human hair. Amino Acids 2018; 50:537-546. [PMID: 29480334 PMCID: PMC5917003 DOI: 10.1007/s00726-018-2545-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 02/20/2018] [Indexed: 12/23/2022]
Abstract
Growing human head hair contains a history of keratin and provides a unique model for studies of protein damage. Here, we examined mechanism of homocysteine (Hcy) accumulation and keratin damage in human hair. We found that the content of Hcy-keratin increased along the hair fiber, with levels 5-10-fold higher levels in older sections at the hair's tip than in younger sections at hair's base. The accumulation of Hcy led to a complete loss of keratin solubility in sodium dodecyl sulfate. The increase in Hcy-keratin was accompanied by a decrease in methionine-keratin. Levels of Hcy-keratin were correlated with hair copper and iron in older hair. These relationships were recapitulated in model experiments in vitro, in which Hcy generation from Met exhibited a similar dependence on copper or iron. Taken together, these findings suggest that Hcy-keratin accumulation is due to copper/iron-catalyzed demethylation of methionine residues and contributes to keratin damage in human hair.
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Affiliation(s)
- Kamila Borowczyk
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers-New Jersey Medical School, International Center for Public Health, 225 Warren Street, Newark, NJ, 07103, USA.,Department of Environmental Chemistry, University of Łódź, 90-236, Łódź, Poland
| | - Joanna Suliburska
- Department of Human Nutrition and Hygiene, Poznań University of Life Sciences, 60-632, Poznań, Poland
| | - Hieronim Jakubowski
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers-New Jersey Medical School, International Center for Public Health, 225 Warren Street, Newark, NJ, 07103, USA. .,Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, 60-632, Poznań, Poland.
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Attenuation of Red Blood Cell Storage Lesions with Vitamin C. Antioxidants (Basel) 2017; 6:antiox6030055. [PMID: 28704937 PMCID: PMC5618083 DOI: 10.3390/antiox6030055] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/06/2017] [Accepted: 07/08/2017] [Indexed: 12/19/2022] Open
Abstract
Stored red blood cells (RBCs) undergo oxidative stress that induces deleterious metabolic, structural, biochemical, and molecular changes collectively referred to as “storage lesions”. We hypothesized that vitamin C (VitC, reduced or oxidized) would reduce red cell storage lesions, thus prolonging their storage duration. Whole-blood-derived, leuko-reduced, SAGM (saline-adenine-glucose-mannitol)-preserved RBC concentrates were equally divided into four pediatric storage bags and the following additions made: (1) saline (saline); (2) 0.3 mmol/L reduced VitC (Lo VitC); (3) 3 mmol/L reduced VitC (Hi VitC); or (4) 0.3 mmol/L oxidized VitC (dehydroascorbic acid, DHA) as final concentrations. Biochemical and rheological parameters were serially assessed at baseline (prior to supplementation) and Days 7, 21, 42, and 56 for RBC VitC concentration, pH, osmotic fragility by mechanical fragility index, and percent hemolysis, LDH release, glutathione depletion, RBC membrane integrity by scanning electron microscopy, and Western blot for β-spectrin. VitC exposure (reduced and oxidized) significantly increased RBC antioxidant status with varying dynamics and produced trends in reduction in osmotic fragility and increases in membrane integrity. Conclusion: VitC partially protects RBC from oxidative changes during storage. Combining VitC with other antioxidants has the potential to improve long-term storage of RBC.
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Vitamin C in Stem Cell Biology: Impact on Extracellular Matrix Homeostasis and Epigenetics. Stem Cells Int 2017; 2017:8936156. [PMID: 28512473 PMCID: PMC5415867 DOI: 10.1155/2017/8936156] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/05/2017] [Indexed: 12/30/2022] Open
Abstract
Transcription factors and signaling molecules are well-known regulators of stem cell identity and behavior; however, increasing evidence indicates that environmental cues contribute to this complex network of stimuli, acting as crucial determinants of stem cell fate. l-Ascorbic acid (vitamin C (VitC)) has gained growing interest for its multiple functions and mechanisms of action, contributing to the homeostasis of normal tissues and organs as well as to tissue regeneration. Here, we review the main functions of VitC and its effects on stem cells, focusing on its activity as cofactor of Fe+2/αKG dioxygenases, which regulate the epigenetic signatures, the redox status, and the extracellular matrix (ECM) composition, depending on the enzymes' subcellular localization. Acting as cofactor of collagen prolyl hydroxylases in the endoplasmic reticulum, VitC regulates ECM/collagen homeostasis and plays a key role in the differentiation of mesenchymal stem cells towards osteoblasts, chondrocytes, and tendons. In the nucleus, VitC enhances the activity of DNA and histone demethylases, improving somatic cell reprogramming and pushing embryonic stem cell towards the naive pluripotent state. The broad spectrum of actions of VitC highlights its relevance for stem cell biology in both physiology and disease.
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Zhao L, Li Z, Zhao L, Zhang C. In Vivo Determination of Reduced Thiols in Rat Cerebellum Paraflocculus Following Salicylate-Induced Tinnitus by Fluorescence. ANAL LETT 2016. [DOI: 10.1080/00032719.2016.1186170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Lingzhi Zhao
- Institute of Pharmacology, Department of Pharmacy, Xi’an Medical College, Xi’an, Shaanxi Province, China
| | - Zhao Li
- Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Department of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an, China
| | - Liu Zhao
- Beijing Research Center of Agricultural Standards and Testing, Beijing, China
| | - Chenxiao Zhang
- Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Department of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an, China
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12
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Dereven’kov IA, Thi TTB, Salnikov DS, Makarov SV. Effect of amino acids on the interaction between cobalamin(II) and dehydroascorbic acid. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2016. [DOI: 10.1134/s0036024416030080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Li Z, Geng ZR, Zhang C, Wang XB, Wang ZL. BODIPY-based azamacrocyclic ensemble for selective fluorescence detection and quantification of homocysteine in biological applications. Biosens Bioelectron 2015; 72:1-9. [DOI: 10.1016/j.bios.2015.04.085] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/16/2015] [Accepted: 04/27/2015] [Indexed: 12/28/2022]
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14
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Keshari KR, Wilson DM, Sai V, Bok R, Jen KY, Larson P, Van Criekinge M, Kurhanewicz J, Wang ZJ. Noninvasive in vivo imaging of diabetes-induced renal oxidative stress and response to therapy using hyperpolarized 13C dehydroascorbate magnetic resonance. Diabetes 2015; 64:344-52. [PMID: 25187363 PMCID: PMC4303960 DOI: 10.2337/db13-1829] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oxidative stress has been proposed to be a unifying cause for diabetic nephropathy and a target for novel therapies. Here we apply a new endogenous reduction-oxidation (redox) sensor, hyperpolarized (HP) (13)C dehydroascorbate (DHA), in conjunction with MRI to noninvasively interrogate the renal redox capacity in a mouse diabetes model. The diabetic mice demonstrate an early decrease in renal redox capacity, as shown by the lower in vivo HP (13)C DHA reduction to the antioxidant vitamin C (VitC), prior to histological evidence of nephropathy. This correlates with lower tissue reduced glutathione (GSH) concentration and higher NADPH oxidase 4 (Nox4) expression, consistent with increased superoxide generation and oxidative stress. ACE inhibition restores the HP (13)C DHA reduction to VitC with concomitant normalization of GSH concentration and Nox4 expression in diabetic mice. HP (13)C DHA enables rapid in vivo assessment of altered redox capacity in diabetic renal injury and after successful treatment.
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Affiliation(s)
- Kayvan R Keshari
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, NY
| | - David M Wilson
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Victor Sai
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Robert Bok
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Kuang-Yu Jen
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Peder Larson
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Mark Van Criekinge
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - John Kurhanewicz
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Zhen J Wang
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA
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16
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Salehzadeh H, Mokhtari B, Nematollahi D. Selective electrochemical determination of homocysteine in the presence of cysteine and glutathione. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2014.01.072] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Bachmann C, Probst B, Guttentag M, Alberto R. Ascorbate as an electron relay between an irreversible electron donor and Ru(ii) or Re(i) photosensitizers. Chem Commun (Camb) 2014; 50:6737-9. [DOI: 10.1039/c4cc01500b] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ascorbate acts as a reversible electron shuttle between tris(2-carboxyethyl) phosphine (TCEP) and ReI or RuII photosensitizers.
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Affiliation(s)
- Cyril Bachmann
- Department of Chemistry
- University of Zürich
- CH-8057 Zürich, Switzerland
| | - Benjamin Probst
- Department of Chemistry
- University of Zürich
- CH-8057 Zürich, Switzerland
| | - Miguel Guttentag
- Department of Chemistry
- University of Zürich
- CH-8057 Zürich, Switzerland
| | - Roger Alberto
- Department of Chemistry
- University of Zürich
- CH-8057 Zürich, Switzerland
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Bohndiek SE, Kettunen MI, Hu DE, Kennedy BWC, Boren J, Gallagher FA, Brindle KM. Hyperpolarized [1-13C]-ascorbic and dehydroascorbic acid: vitamin C as a probe for imaging redox status in vivo. J Am Chem Soc 2011; 133:11795-801. [PMID: 21692446 PMCID: PMC3144679 DOI: 10.1021/ja2045925] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Indexed: 01/12/2023]
Abstract
Dynamic nuclear polarization (DNP) of (13)C-labeled metabolic substrates in vitro and their subsequent intravenous administration allow both the location of the hyperpolarized substrate and the dynamics of its subsequent conversion into other metabolic products to be detected in vivo. We report here the hyperpolarization of [1-(13)C]-ascorbic acid (AA) and [1-(13)C]-dehydroascorbic acid (DHA), the reduced and oxidized forms of vitamin C, respectively, and evaluate their performance as probes of tumor redox state. Solution-state polarization of 10.5 ± 1.3% was achieved for both forms at pH 3.2, whereas at pH 7.0, [1-(13)C]-AA retained polarization of 5.1 ± 0.6% and [1-(13)C]-DHA retained 8.2 ± 1.1%. The spin-lattice relaxation times (T(1)'s) for these labeled nuclei are long at 9.4 T: 15.9 ± 0.7 s for AA and 20.5 ± 0.9 s for DHA. Extracellular oxidation of [1-(13)C]-AA and intracellular reduction of [1-(13)C]-DHA were observed in suspensions of murine lymphoma cells. The spontaneous reaction of DHA with the cellular antioxidant glutathione was monitored in vitro and was approximately 100-fold lower than the rate observed in cell suspensions, indicating enzymatic involvement in the intracellular reduction. [1-(13)C]-DHA reduction was also detected in lymphoma tumors in vivo. In contrast, no detectable oxidation of [1-(13)C]-AA was measured in the same tumors, consistent with the notion that tumors maintain a reduced microenvironment. This study demonstrates that hyperpolarized (13)C-labeled vitamin C could be used as a noninvasive biomarker of redox status in vivo, which has the potential to translate to the clinic.
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Affiliation(s)
- Sarah E. Bohndiek
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K., and Cancer Research UK Cambridge Research Institute, Li-Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K
| | - Mikko I. Kettunen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K., and Cancer Research UK Cambridge Research Institute, Li-Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K
| | - De-en Hu
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K., and Cancer Research UK Cambridge Research Institute, Li-Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K
| | - Brett W. C. Kennedy
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K., and Cancer Research UK Cambridge Research Institute, Li-Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K
| | - Joan Boren
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K., and Cancer Research UK Cambridge Research Institute, Li-Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K
| | - Ferdia A. Gallagher
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K., and Cancer Research UK Cambridge Research Institute, Li-Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K
| | - Kevin M. Brindle
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K., and Cancer Research UK Cambridge Research Institute, Li-Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K
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Sun SK, Wang HF, Yan XP. A sensitive and selective resonance light scattering bioassay for homocysteine in biological fluids based on target-involved assembly of polyethyleneimine-capped Ag-nanoclusters. Chem Commun (Camb) 2011; 47:3817-9. [DOI: 10.1039/c0cc04463f] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Corti A, Casini AF, Pompella A. Cellular pathways for transport and efflux of ascorbate and dehydroascorbate. Arch Biochem Biophys 2010; 500:107-15. [PMID: 20494648 DOI: 10.1016/j.abb.2010.05.014] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 05/13/2010] [Accepted: 05/14/2010] [Indexed: 11/17/2022]
Abstract
The mechanisms allowing the cellular transport of ascorbic acid represent a primary aspect for the understanding of the roles played by this vitamin in pathophysiology. Considerable research effort has been spent in the field, on several animal models and different cell types. Several mechanisms have been described to date, mediating the movements of different redox forms of ascorbic acid across cell membranes. Vitamin C can enter cells both in its reduced and oxidized form, ascorbic acid (AA) and dehydroascorbate (DHA), utilizing respectively sodium-dependent transporters (SVCT) or glucose transporters (GLUT). Modulation of SVCT expression and function has been described by cytokines, steroids and post-translational protein modification. Cellular uptake of DHA is followed by its intracellular reduction to AA by several enzymatic and non-enzymatic systems. Efflux of vitamin C has been also described in a number of cell types and different pathophysiological functions were proposed for this phenomenon, in dependence of the cell model studied. Cellular efflux of AA is mediated through volume-sensitive (VSOAC) and Ca(2+)-dependent anion channels, gap-junction hemichannels, exocytosis of secretory vesicles and possibly through homo- and hetero-exchange systems at the plasma membrane level. Altogether, available data suggest that cellular efflux of ascorbic acid - besides its uptake - should be taken into account when evaluating the cellular homeostasis and functions of this important vitamin.
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Affiliation(s)
- Alessandro Corti
- Dipartimento di Patologia Sperimentale, Università di Pisa, Italy.
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21
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Xia YS, Zhu CQ. Interaction of CdTe nanocrystals with thiol-containing amino acids at different pH: a fluorimetric study. Mikrochim Acta 2008. [DOI: 10.1007/s00604-008-0025-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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22
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Poljsak B, Gazdag Z, Jenko-Brinovec S, Fujs S, Pesti M, Bélagyi J, Plesnicar S, Raspor P. Pro-oxidative vs antioxidative properties of ascorbic acid in chromium(VI)-induced damage: an in vivo and in vitro approach. J Appl Toxicol 2006; 25:535-48. [PMID: 16092082 DOI: 10.1002/jat.1093] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The effect of antioxidant ascorbic acid (vitamin C) pretreatment on chromium(VI)-induced damage was investigated using the yeast Saccharomyces cerevisiae as a model organism. The objective of this study was to pretreat yeast cells with the antioxidant ascorbic acid in an effort to increase cell tolerance against reactive chromium intermediates and reactive oxygen species formed during chromium(VI) reduction. Intracellular oxidation was estimated using the fluorescence indicators dihidro-2,7-dichlorofluorescein, dihydroethidium and dihydrorhodamine 123. The role of ascorbic acid pretreatment on chromium(VI) toxicity was determined by measuring mitotic gene conversion, reverse mutations, 8-OHdG, hydroxyl radical, superoxide anion and chromium(V) formation. The chromium content in the biomass was determined by flame atomic absorption spectrometry. In the absence of chromium, ascorbic acid effectively protected the cells against endogenous reactive oxygen species formed during normal cellular metabolism. In vitro measurements employing EPR and the results of supercoiled DNA cleavage revealed that the pro-oxidative action of ascorbic acid during Cr(VI) reduction was concentration-dependent and that harmful hydroxyl radical and Cr(V) had formed following Cr(VI) reduction. However, the in vivo results highlighted the important role of increased cytosol reduction capacity related to modification of Cr(V) formation, increased chromium accumulation, better scavenging ability of superoxide anions and hydrogen peroxide, and consequently decreased cytotoxicity and genotoxicity in ascorbic acid pretreated cells. Ascorbic acid influenced Cr(VI) toxicity both as a reducing agent, by decreasing Cr(V) persistence, and as an antioxidant, by decreasing intracellular superoxide anion and hydrogen peroxide formation and by quenching free radicals formed during Cr(VI) to Cr(III) reduction. Increased 8-OHdG and decreased reduced glutathione in ascorbic acid-treated cells might induce an endogenous antioxidant defense system and thus increase cell tolerance against subsequent Cr-induced stress.
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Affiliation(s)
- B Poljsak
- University Polytechnic Nova Gorica, School of Environmental Science, Vipavska 13, 5000 Nova Gorica, Slovenia
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Linetsky M, Shipova EV, Argirov OK. Influence of glutathione fructosylation on its properties. Arch Biochem Biophys 2006; 449:34-46. [PMID: 16579954 DOI: 10.1016/j.abb.2006.02.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2006] [Revised: 02/06/2006] [Accepted: 02/23/2006] [Indexed: 10/24/2022]
Abstract
Incubation of fructose and glutathione leads to the formation of N-2-deoxy-glucos-2-yl glutathione as the major glycation product, with characteristic positive ion at 470 Th in LC-MS spectra. Glutathione disulfide and fructose generate two compounds: N-2-deoxy-glucos-2-yl glutathione disulfide (m/z=775 Th) and bis di-N,N'-2-deoxy-glucos-2-yl glutathione disulfide (m/z=937 Th). N-2-deoxy-glucos-2-yl glutathione is 2.5-fold less effective than glutathione in reducing dehydroascorbic acid. Glutathione peroxidase and glutahione-S-transferase exhibit marginal activity toward N-2-deoxy-glucos-2-yl glutathione, while glyoxalase I shows 44.9% of the enzyme's specific activity. Glutathione reductase demonstrates 6.9% of the enzyme's specific activity with bis di-N,N'-2-deoxy-glucos-2-yl glutathione, while with mono-N-glucosyl glutathione disulfide retained 5 6.1% of the original activity. Glutathione reductase could not reduce N-2-deoxy-glucos-2-yl glutathione in mixed disulfide with gammaS-crystallin, but reduced glutathione in mixed disulfide with gammaS-crystallin by 90%. The presence of N-2-deoxy-glucos-2-yl glutathione in mixed disulfide with gammaS-crystallin makes this molecule more susceptible to unfolding than native gammaS-crystallin.
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Affiliation(s)
- Mikhail Linetsky
- Mason Eye Institute, University of Missouri, Columbia, MO 65201, USA.
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Pfanzagl B. Ascorbate is particularly effective against LDL oxidation in the presence of iron(III) and homocysteine/cystine at acidic pH. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1736:237-43. [PMID: 16169276 DOI: 10.1016/j.bbalip.2005.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Revised: 08/10/2005] [Accepted: 08/12/2005] [Indexed: 11/24/2022]
Abstract
Metal-catalyzed LDL oxidation is enhanced by the presence of homocysteine. In this study, the effectiveness of ascorbic acid against low-density lipoprotein (LDL) oxidation by iron(III) and copper(II) in the presence of homocysteine and the main plasma disulfide cystine was investigated. Relative to the degree of LDL oxidation reached in the absence of antioxidants, ascorbic acid was particularly effective against iron-catalyzed LDL oxidation at pH 6.0. This can be explained from its stability under acidic conditions and is likely to be important in ischemia, in inflammation and exhausting exercise. At pH 7.4, an ascorbic acid concentration at least as high as the concentration of homocysteine might be necessary to efficiently inhibit LDL oxidation by iron(III) and copper(II) in the presence of homocysteine and cystine. Histidine increased the efficiency of ascorbic acid as an antioxidant against copper-mediated oxidation in this system. The capacity of homocysteine to regenerate ascorbic acid from dehydroascorbic acid appeared to play a minor role in inhibition of ascorbic acid oxidation by copper as compared to copper chelation by homocysteine.
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Affiliation(s)
- Beatrix Pfanzagl
- Institute of Physiology, Center of Physiology and Pathophysiology, Medical University Vienna, Schwarzspanierstrasse 17, A-1090 Wien, Austria.
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25
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Stipanuk MH. Sulfur amino acid metabolism: pathways for production and removal of homocysteine and cysteine. Annu Rev Nutr 2004; 24:539-77. [PMID: 15189131 DOI: 10.1146/annurev.nutr.24.012003.132418] [Citation(s) in RCA: 687] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Tissue concentrations of both homocysteine (Hcy) and cysteine (Cys) are maintained at low levels by regulated production and efficient removal of these thiols. The regulation of the metabolism of methionine and Cys is discussed from the standpoint of maintaining low levels of Hcy and Cys while, at the same time, ensuring an adequate supply of these thiols for their essential functions. S-Adenosylmethionine coordinately regulates the flux through remethylation and transsulfuration, and glycine N-methyltransferase regulates flux through transmethylation and hence the S-adenosylmethionine/S-adenosylhomocysteine ratio. Cystathionine beta-synthase activity is also regulated in response to the redox environment, and transcription of the gene is hormonally regulated in response to fuel supply (insulin, glucagon, and glucocorticoids). The H2S-producing capacity of cystathionine gamma-lyase may be regulated in response to nitric oxide. Cys is substrate for a variety of anabolic and catabolic enzymes. Its concentration is regulated primarily by hepatic Cys dioxygenase; the level of Cys dioxygenase is upregulated in a Cys-responsive manner via a decrease in the rate of polyubiquitination and, hence, degradation by the 26S proteasome.
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Affiliation(s)
- Martha H Stipanuk
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA.
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Abstract
Homocysteine (Hcy) is a biomarker for significant disorders including Alzheimer's and cardiovascular disease. The monitoring of Hcy levels in plasma is of current concern. We describe highly selective colorimetric methods for the direct detection of Hcy. Inexpensive, commercially available materials are employed. The results show potential application for the detection of Hcy in human blood plasma.
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Alul RH, Wood M, Longo J, Marcotte AL, Campione AL, Moore MK, Lynch SM. Vitamin C protects low-density lipoprotein from homocysteine-mediated oxidation. Free Radic Biol Med 2003; 34:881-91. [PMID: 12654477 DOI: 10.1016/s0891-5849(03)00028-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Homocysteine, an atherogenic amino acid, promotes iron-dependent oxidation of low-density lipoprotein (LDL). We investigated whether vitamin C, a physiological antioxidant, could protect LDL from homocysteine-mediated oxidation. LDL (0.2 mg of protein/ml) was incubated at 37 degrees C with homocysteine (1000 microM) and ferric iron (10-100 microM) in either the absence (control) or presence of vitamin C (5-250 microM). Under these conditions, vitamin C protected LDL from oxidation as evidenced by an increased lag time preceding lipid diene formation (> or = 5 vs. 2.5 h for control), decreased thiobarbituric acid-reactive substances accumulation (< or = 19 +/- 1 nmol/mg when vitamin C > or = 10 microM vs. 32 +/- 3 nmol/mg for control, p <.01), and decreased lipoprotein anodic electrophoretic mobility. Near-maximal protection was observed at vitamin C concentrations similar to those in human blood (50-100 microM); also, some protection was observed even at low concentrations (5-10 microM). This effect resulted neither from altered iron redox chemistry nor enhanced recycling of vitamin E in LDL. Instead, similar to previous reports for copper-dependent LDL oxidation, we found that vitamin C protected LDL from homocysteine-mediated oxidation through covalent lipoprotein modification involving dehydroascorbic acid. Protection of LDL from homocysteine-mediated oxidation by vitamin C may have implications for the prevention of cardiovascular disease.
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Affiliation(s)
- Rushdi H Alul
- Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA
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