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Urate hydroperoxide oxidizes endothelial cell surface protein disulfide isomerase-A1 and impairs adherence. Biochim Biophys Acta Gen Subj 2019; 1864:129481. [PMID: 31734460 DOI: 10.1016/j.bbagen.2019.129481] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 11/07/2019] [Accepted: 11/12/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Extracellular surface protein disulfide isomerase-A1 (PDI) is involved in platelet aggregation, thrombus formation and vascular remodeling. PDI performs redox exchange with client proteins and, hence, its oxidation by extracellular molecules might alter protein function and cell response. In this study, we investigated PDI oxidation by urate hydroperoxide, a newly-described oxidant that is generated through uric acid oxidation by peroxidases, with a putative role in vascular inflammation. METHODS Amino acids specificity and kinetics of PDI oxidation by urate hydroperoxide was evaluated by LC-MS/MS and by stopped-flow. Oxidation of cell surface PDI and other thiol-proteins from HUVECs was identified using impermeable alkylating reagents. Oxidation of intracellular GSH and GSSG was evaluated with specific LC-MS/MS techniques. Cell adherence, detachment and viability were assessed using crystal violet staining, cellular microscopy and LDH activity, respectively. RESULTS Urate hydroperoxide specifically oxidized cysteine residues from catalytic sites of recombinant PDI with a rate constant of 6 × 103 M-1 s-1. Incubation of HUVECs with urate hydroperoxide led to oxidation of cell surface PDI and other unidentified cell surface thiol-proteins. Cell adherence to fibronectin coated plates was impaired by urate hydroperoxide, as well as by other oxidants, thiol alkylating agents and PDI inhibitors. Urate hydroperoxide did not affect cell viability but significantly decreased GSH/GSSG ratio. CONCLUSIONS Our results demonstrated that urate hydroperoxide affects thiol-oxidation of PDI and other cell surface proteins, impairing cellular adherence. GENERAL SIGNIFICANCE These findings could contribute to a better understanding of the mechanism by which uric acid affects endothelial cell function and vascular homeostasis.
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Peixoto ÁS, Geyer RR, Iqbal A, Truzzi DR, Soares Moretti AI, Laurindo FRM, Augusto O. Peroxynitrite preferentially oxidizes the dithiol redox motifs of protein-disulfide isomerase. J Biol Chem 2018; 293:1450-1465. [PMID: 29191937 PMCID: PMC5787819 DOI: 10.1074/jbc.m117.807016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 11/29/2017] [Indexed: 12/22/2022] Open
Abstract
Protein-disulfide isomerase (PDI) is a ubiquitous dithiol-disulfide oxidoreductase that performs an array of cellular functions, such as cellular signaling and responses to cell-damaging events. PDI can become dysfunctional by post-translational modifications, including those promoted by biological oxidants, and its dysfunction has been associated with several diseases in which oxidative stress plays a role. Because the kinetics and products of the reaction of these oxidants with PDI remain incompletely characterized, we investigated the reaction of PDI with the biological oxidant peroxynitrite. First, by determining the rate constant of the oxidation of PDI's redox-active Cys residues (Cys53 and Cys397) by hydrogen peroxide (k = 17.3 ± 1.3 m-1 s-1 at pH 7.4 and 25 °C), we established that the measured decay of the intrinsic PDI fluorescence is appropriate for kinetic studies. The reaction of these PDI residues with peroxynitrite was considerably faster (k = (6.9 ± 0.2) × 104 m-1 s-1), and both Cys residues were kinetically indistinguishable. Limited proteolysis, kinetic simulations, and MS analyses confirmed that peroxynitrite preferentially oxidizes the redox-active Cys residues of PDI to the corresponding sulfenic acids, which reacted with the resolving thiols at the active sites to produce disulfides (i.e. Cys53-Cys56 and Cys397-Cys400). A fraction of peroxynitrite, however, decayed to radicals that hydroxylated and nitrated other active-site residues (Trp52, Trp396, and Tyr393). Excess peroxynitrite promoted further PDI oxidation, nitration, inactivation, and covalent oligomerization. We conclude that these PDI modifications may contribute to the pathogenic mechanism of several diseases associated with dysfunctional PDI.
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Affiliation(s)
- Álbert Souza Peixoto
- From the Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, CEP 05508-000, Brazil and
| | - R Ryan Geyer
- From the Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, CEP 05508-000, Brazil and
| | - Asif Iqbal
- From the Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, CEP 05508-000, Brazil and
| | - Daniela R Truzzi
- From the Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, CEP 05508-000, Brazil and
| | - Ana I Soares Moretti
- Vascular Biology Laboratory, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, CEP 05403-000, Brazil
| | - Francisco R M Laurindo
- Vascular Biology Laboratory, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, CEP 05403-000, Brazil
| | - Ohara Augusto
- From the Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, CEP 05508-000, Brazil and
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Wheelock AM, Goto S. Effects of post-electrophoretic analysis on variance in gel-based proteomics. Expert Rev Proteomics 2014; 3:129-42. [PMID: 16445357 DOI: 10.1586/14789450.3.1.129] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
2D electrophoresis (2DE) is a prominent separation method for complex proteomes. Although recent advances have increased the utility of this method in quantitative proteomics studies, many sources of variance still exist. This review discusses the post-electrophoretic sources of variance in current 2DE analysis. The essential improvements in protein visualization and software algorithms that have made 2DE a leading quantitative proteomics method are briefly reviewed. A number of shortcomings in the post-electrophoretic analysis of 2DE data that require further attention are highlighted. Topics discussed include protein visualization and image acquisition, internal standards and normalization methods, background subtraction algorithms, normality of distribution, and the need for standardized tests for the evaluation of 2DE analysis software packages.
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Affiliation(s)
- Asa M Wheelock
- Kyoto University, Bioinformatics Center, Institute for Chemical Research, Uji, Kyoto, 611-0011, Japan.
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Analysis of naphthalene adduct binding sites in model proteins by tandem mass spectrometry. Chem Biol Interact 2012; 199:120-8. [PMID: 22659010 DOI: 10.1016/j.cbi.2012.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 05/16/2012] [Accepted: 05/23/2012] [Indexed: 12/15/2022]
Abstract
The electrophilic metabolites of the polyaromatic hydrocarbon naphthalene have been shown to bind covalently to proteins and covalent adduct formation correlates with the cytotoxic effects of the chemical in the respiratory system. Although 1,2-naphthalene epoxide, naphthalene diol epoxide, 1,2-naphthoquinone, and 1,4-napthoquinone have been identified as reactive metabolites of interest, the role of each metabolite in total covalent protein adduction and subsequent cytotoxicity remains to be established. To better understand the target residues associated with the reaction of these metabolites with proteins, mass spectrometry was used to identify adducted residues following (1) incubation of metabolites with actin and protein disulfide isomerase (PDI), and (2) activation of naphthalene in microsomal incubations containing supplemental actin or PDI. All four reactive metabolites bound to Cys, Lys or His residues in actin and PDI. Cys₁₇ of actin was the only residue adducted by all metabolites; there was substantial metabolite selectivity for the majority of adducted residues. Modifications of actin and PDI, following microsomal incubations containing ¹⁴C-naphthalene, were detected readily by 2D gel electrophoresis and phosphor imaging. However, target modifications on tryptic peptides from these isolated proteins could not be readily detected by MALDI/TOF/TOF and only three modified peptides were detected using high resolution-selective ion monitoring (HR-SIM). All the reactive metabolites investigated have the potential to modify several residues in a single protein, but even in tissues with very high rates of naphthalene activation, the extent of modification was too low to allow unambiguous identification of a significant number of modified residues in the isolated proteins.
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Pohanka M, Sobotka J, Jilkova M, Stetina R. Oxidative stress after sulfur mustard intoxication and its reduction by melatonin: efficacy of antioxidant therapy during serious intoxication. Drug Chem Toxicol 2010; 34:85-91. [PMID: 20958112 DOI: 10.3109/01480545.2010.505238] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sulfur mustard (SM) is an important chemical warfare agent. The mechanism of SM toxicity still has not been fully recognized. However, oxidative stress and following the damaging of macromolecules in the human body is considered one of the crucial steps in SM toxicity. Rats intoxicated with pure (i.e., distilled) SM were used as a model organism. The doses, 0 (control), 5, 20, and 80 mg/kg of body weight, were applied intradermally. A hormone with strong antioxidant potency, melatonin, was applied (25 and 50 mg/kg, subcutaneously) into the other group of rats exposed with the same doses of SM. Total plasma protein, ferric-reducing antioxidant power (FRAP), thiobarbituric-acid-reactive substances (TBARS), and plasma protein carbonyls were assayed in blood plasma. A significant decrease of total plasma proteins was found for control, and the lowest dose of SM was treated with melatonin. Melatonin was also able to enhance the production of low-molecular-weight antioxidants, as the SM-intoxicated rats had significantly (P ≤ 0.01) increasing FRAP levels after intoxication with SM in doses of 20 and 80 mg/kg, when compared to the control treated with melatonin. Melatonin also decreased TBARS level, representing reduced lipid peroxidation (LPO). However, LPO seems to be of less importance for SM toxic impact. The more reliable parameter was the level of total plasma protein carbonyls. The carbonyl levels were significantly increased due to SM, and the carbonylation was slowed due to melatonin intake. In conclusion, melatonin seems to be a prospective compound in reducing SM toxicity impact in the rat.
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Affiliation(s)
- Miroslav Pohanka
- Center of Advanced Studies, University of Defence/Trebesska 1575, Hradec Kralove, Czech Republic.
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Pohanka M, Stetina R. Shift of oxidants and antioxidants levels in rats as a reaction to exposure to sulfur mustard. J Appl Toxicol 2009; 29:643-7. [DOI: 10.1002/jat.1451] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Liebler DC. Protein damage by reactive electrophiles: targets and consequences. Chem Res Toxicol 2007; 21:117-28. [PMID: 18052106 DOI: 10.1021/tx700235t] [Citation(s) in RCA: 197] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
It has been 60 years since the Millers first described the covalent binding of carcinogens to tissue proteins. Protein covalent binding was gradually overshadowed by the emergence of DNA adduct formation as the dominant paradigm in chemical carcinogenesis but re-emerged in the early 1970s as a critical mechanism of drug and chemical toxicity. Technology limitations hampered the characterization of protein adducts until the emergence of mass spectrometry-based proteomics in the late 1990s. The time since then has seen rapid progress in the characterization of the protein targets of electrophiles and the consequences of protein damage. Recent integration of novel affinity chemistries for electrophile probes, shotgun proteomics methods, and systems modeling tools has led to the identification of hundreds of protein targets of electrophiles in mammalian systems. The technology now exists to map the targets of damage to critical components of signaling pathways and metabolic networks and to understand mechanisms of damage at a systems level. The implementation of sensitive, specific analyses for protein adducts from both xenobiotic-derived and endogenous electrophiles offers a means to link protein damage to clinically relevant health effects of both chemical exposures and disease processes.
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Affiliation(s)
- Daniel C Liebler
- Department of Biochemistry, Vanderbilt University School of Medicine,, Nashville, Tennessee 37232, USA.
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Shin NY, Liu Q, Stamer SL, Liebler DC. Protein targets of reactive electrophiles in human liver microsomes. Chem Res Toxicol 2007; 20:859-67. [PMID: 17480101 PMCID: PMC2556149 DOI: 10.1021/tx700031r] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Liver microsomes are widely used to study xenobiotic metabolism in vitro, and covalent binding to microsomal proteins serves as a surrogate marker for toxicity mediated by reactive metabolites. We have applied liquid chromatography-tandem mass spectrometry (LC-MS-MS) to identify protein targets of the biotin-tagged model electrophiles 1-biotinamido-4-(4'-[maleimidoethylcyclohexane]-carboxamido)butane (BMCC) and N-iodoacetyl-N-biotinylhexylenediamine (IAB) in human liver microsomes. The biotin-tagged peptides resulting from in-gel tryptic digestion were enriched by biotin-avidin chromatography and LC-MS-MS was used to identify 376 microsomal cysteine thiol targets of BMCC and IAB in 263 proteins. Protein adduction was selective and reproducible, and only 90 specific cysteine sites in 70 proteins (approximately 25% of the total) were adducted by both electrophiles. Differences in adduction selectivity correlated with different biological effects of the compounds, as IAB- but not BMCC-induced ER stress in HEK293 cells. Targeted LC-MS-MS analysis of microsomal glutathione-S-transferase cysteine 50, a target of both IAB and BMCC, detected time-dependent adduction by the reactive acetaminophen metabolite N-acetyl-p-benzoquinoneimine during microsomal incubations. The results indicate that electrophiles selectively adduct microsomal proteins, but display differing target selectivities that correlate with differences in toxicity. Analysis of selected microsomal protein adduction reactions thus could provide a more specific indication of potential toxicity than bulk covalent binding of radiolabeled compounds.
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Affiliation(s)
| | | | | | - Daniel C. Liebler
- Author to whom correspondence should be addressed at: Department of Biochemistry, Vanderbilt University School of Medicine, Rm. U1213C Medical Research Building III, 465 21 Avenue South, Nashville, TN 37232-8575, Phone 615 322-3063, FAX 615 343-8372,
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Kozarova A, Sliskovic I, Mutus B, Simon ES, Andrews PC, Vacratsis PO. Identification of redox sensitive thiols of protein disulfide isomerase using isotope coded affinity technology and mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:260-9. [PMID: 17074504 DOI: 10.1016/j.jasms.2006.09.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 08/29/2006] [Accepted: 09/27/2006] [Indexed: 05/12/2023]
Abstract
Regulation of the redox state of protein disulfide isomerase (PDI) is critical for its various catalytic functions. Here we describe a procedure utilizing isotope-coded affinity tag (ICAT) technology and mass spectrometry that quantitates relative changes in the dynamic thiol and disulfide states of human PDI. Human PDI contains six cysteine residues, four present in two active sites within the a and a' domains, and two present in the b' domain. ICAT labeling of human PDI indicates a difference between the redox state of the two active sites. Furthermore, under auto-oxidation conditions an approximately 80% decrease in available thiols within the a domain was detected. Surprisingly, the redox state of one of the two cysteines, Cys-295, within the b' domain was altered between the fully reduced and the auto-oxidized state of PDI while the other b' domain cysteine remained fully reduced. An interesting mono- and dioxidation modification of an invariable tryptophan residue, Trp-35, within the active site was also mapped by tandem mass spectrometry. Our findings indicate that ICAT methodology in conjunction with mass spectrometry represents a powerful tool to monitor changes in the redox state of individual cysteine residues within PDI under various conditions.
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Affiliation(s)
- Anna Kozarova
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada
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Wheelock AM, Morin D, Bartosiewicz M, Buckpitt AR. Use of a fluorescent internal protein standard to achieve quantitative two-dimensional gel electrophoresis. Proteomics 2006; 6:1385-98. [PMID: 16429456 DOI: 10.1002/pmic.200402083] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
2-DE is a powerful separation method for complex protein mixtures. However, large intergel variations in spot intensity limit its use for quantitative proteomics studies. To address this issue, we developed a fluorescent internal protein standard for use in 2-DE analysis. Protein samples are spiked with an Alexa-labeled internal standard (ALIS) prior to separation with 2-DE. Due to the high extinction coefficient of the Alexa-fluor, incorporation of 0.1% of total protein is sufficient to allow visualization of the internal standard yet low enough to avoid interference in subsequent quantification and identification steps. Following 2-DE, total proteins are visualized with fluorescent postelectrophoretic stains spectrally separated from ALIS. Four protein stains, Deep Purple, Sulforhodamine G, ruthenium II-tris(bathophenanthroline disulfonate) (RuTBS), and SYPRO Ruby, including improved purification and staining protocols for RuTBS and ten-fold dilutions of SYPRO Ruby were evaluated. All staining protocols were compatible with the ALIS method and had similar LODs (1-4 ng) and dynamic ranges (10(3)). ALIS is a powerful normalization method for quantitative 2-DE which avoids potential problems associated with dual spot migration patterns observed in the DIGE method. Furthermore, ALIS provides significantly improved normality in the distribution of spot abundance-variance compared to normalization through division by the total spot volume.
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Affiliation(s)
- Asa M Wheelock
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
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Isbell MA, Morin D, Boland B, Buckpitt A, Salemi M, Presley J. Identification of proteins adducted by reactive naphthalene metabolitesin vitro. Proteomics 2005; 5:4197-204. [PMID: 16206326 DOI: 10.1002/pmic.200401278] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Metabolic activation of inert chemicals to electrophilic intermediates has been correlated with the incidence and severity of cytotoxicity. The current studies have identified several proteins adducted by reactive metabolites of the lung toxicant, naphthalene. Proteins isolated from microsomal incubations of (14)C-naphthalene were separated by 2-DE, proteins were blotted to PVDF membranes and radioactive proteins were localized by storage phosphor analysis. Adducted proteins were isolated from complimentary gels and identified by peptide mass mapping. A total of 18 adducted proteins were identified including: protein disulfide isomerase precursor, ER-60 protease, alpha actin, mouse urinary proteins, and cytochrome b5 reductase. In supernatant fractions, protein disulfide isomerase, heat shock protein 70, and alpha-actin were key proteins to which reactive naphthalene metabolites were bound. All of the proteins adducted, with the exception of cytochrome b5 reductase were sulfhydryl rich. Although several of the proteins found to be adducted in these studies have also been shown to be adducted by other electrophiles, several others have not been reported as common targets of reactive metabolites. These studies provide a basis for both in situ and in vivo work designed to follow the fate and formation of reactive metabolite protein adducts.
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Affiliation(s)
- Margaret A Isbell
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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Lin CY, Isbell MA, Morin D, Boland BC, Salemi MR, Jewell WT, Weir AJ, Fanucchi MV, Baker GL, Plopper CG, Buckpitt AR. Characterization of a Structurally Intact in Situ Lung Model and Comparison of Naphthalene Protein Adducts Generated in This Model vs Lung Microsomes. Chem Res Toxicol 2005; 18:802-13. [PMID: 15892573 DOI: 10.1021/tx049746r] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Airway epithelial cells are a susceptible site for injury by ambient air toxicants such as naphthalene that undergo P450-dependent metabolic activation. The metabolism of naphthalene in Clara cells to reactive intermediates that bind covalently to proteins correlates with cell toxicity. Although several proteins adducted by reactive naphthalene metabolites were identified in microsomal incubations, new methods that maintain the structural integrity of the lung are needed to examine protein targets. Therefore, we developed a method that involves inflation of the lungs via the trachea with medium containing (14)C-naphthalene followed by incubation in situ. The viability of this preparation is supported by maintenance of glutathione levels, rates of naphthalene metabolism, and exclusion of ethidium homodimer-1 from airway epithelium. Following in situ incubation, the levels of adduct per milligram of protein were measured in proteins obtained from bronchoalveolar lavage, epithelial cells, and remaining lung. The levels of adducted proteins obtained in lavage and epithelial cells were similar and were 20-fold higher than those in residual lung tissue. (14)C-Labeled adducted proteins were identified by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) and quadrupole-TOF MS/MS. Major adducted proteins include cytoskeletal proteins, proteins involved in folding and translocation, ATP synthase, extracellular proteins, redox proteins, and selenium binding proteins. We conclude that in situ incubation maintains structural integrity of the lung while allowing examination of reactive intermediate activation and interaction with target cell proteins of the lung. The proteins adducted and identified from in situ incubations were not the same proteins identified from microsomal incubations.
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Affiliation(s)
- Ching Yu Lin
- Department of Molecular Biosciences, School of Veterinary Medicine, Molecular Structure Facility, University of California, Davis, California 95616, USA.
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