Relevant bibliographies by topics / Proteins thiol

Academic literature on the topic 'Proteins thiol'

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Published: 9 March 2023
Last updated: 10 March 2023

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Journal articles on the topic "Proteins thiol"

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Skaff, Ojia, David I. Pattison, and Michael J. Davies. "Hypothiocyanous acid reactivity with low-molecular-mass and protein thiols: absolute rate constants and assessment of biological relevance." Biochemical Journal 422, no. 1 (July 29, 2009): 111–17. http://dx.doi.org/10.1042/bj20090276.

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MPO (myeloperoxidase) catalyses the oxidation of chloride, bromide and thiocyanate by H2O2 to HOCl (hypochlorous acid), HOBr (hypobromous acid) and HOSCN (hypothiocyanous acid, also know as cyanosulfenic acid) respectively. Specificity constants indicate that thiocyanate, SCN−, is a major substrate for MPO. HOSCN is also a major oxidant generated by other peroxidases including salivary, gastric and eosinophil peroxidases. Whereas HOCl and HOBr are powerful oxidizing agents, HOSCN appears to be a less reactive, but more thiol-specific oxidant. Although it is established that HOSCN selectively targets thiols, absolute kinetic data for the reactions of thiols with HOSCN are absent from the literature. This study shows for the first time that the reactions of HOSCN with low-molecular-mass thiol residues occur with rate constants in the range from 7.3×103 M−1·s−1 (for N-acetyl-cysteine at pH 7.4) to 7.7×106 M−1·s−1 (for 5-thio-2-nitrobenzoic acid at pH 6.0). An inverse relationship between the rate of reaction and the pKa of the thiol group was observed. The rates of reaction of HOSCN with thiol-containing proteins were also investigated for four proteins (creatine kinase, BSA, β-lactoglobulin and β-L-crystallins). The values obtained for cysteine residues on these proteins are in the range 1×104– 7×104 M−1·s−1. These second-order rate constants indicate that HOSCN is a major mediator of thiol oxidation in biological systems exposed to peroxidase/H2O2 systems at (patho)physiological concentrations of halide and SCN− ions, and that HOSCN may play an important role in inflammation-induced oxidative damage.
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Venkatraman, Aparna, Aimee Landar, Ashley J. Davis, Elena Ulasova, Grier Page, Michael P. Murphy, Victor Darley-Usmar, and Shannon M. Bailey. "Oxidative modification of hepatic mitochondria protein thiols: effect of chronic alcohol consumption." American Journal of Physiology-Gastrointestinal and Liver Physiology 286, no. 4 (April 2004): G521—G527. http://dx.doi.org/10.1152/ajpgi.00399.2003.

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Redox modification of mitochondrial proteins is thought to play a key role in regulating cellular function, although direct evidence to support this hypothesis is limited. Using an in vivo model of mitochondrial redox stress, ethanol hepatotoxicity, the modification of mitochondrial protein thiols was examined using a proteomics approach. Specific labeling of reduced thiols in the mitochondrion from the livers of control and ethanol-fed rats was achieved by using the thiol reactive compound (4-iodobutyl)triphenylphosphonium (IBTP). This molecule selectively accumulates in the organelle and can be used to identify thiol-containing proteins. Mitochondrial proteins that have been modified are identified by decreased labeling with IBTP using two-dimensional SDS-PAGE followed by immunoblotting with an antibody directed against the triphenylphosphonium moiety of the IBTP molecule. Analyses of these data showed a significant decrease in IBTP labeling of thiols present in specific mitochondria matrix proteins from ethanol-fed rats compared with their corresponding controls. These proteins were identified as the low- Km aldehyde dehydrogenase and glucose-regulated protein 78. The decrease in IBTP labeling in aldehyde dehydrogenase was accompanied by a decrease in specific activity of the enzyme. These data demonstrate that mitochondrial protein thiol modification is associated with chronic alcohol intake and might contribute to the pathophysiology associated with hepatic injury. Taken together, we have developed a protocol to chemically tag and select thiol-modified proteins that will greatly enhance efforts to establish posttranslational redox modification of mitochondrial protein in in vivo models of oxidative or nitrosative stress.
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Ferraro, Anna, Anna Giartosio, Margherita Eufemi, Donatella Barra, Fabio Altieri, and Carlo Turano. "Thiol proteins in chromatin." Bioscience Reports 6, no. 3 (March 1, 1986): 257–63. http://dx.doi.org/10.1007/bf01115154.

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Total half-cystine residues in proteins of pig liver chromatin have been measured. About half of them are present in the reduced state. Thiol groups of non-historic chromatin proteins, which amount to about 40 nmol/mg of protein, are preferentially located in chromatin fragments which are more easily solubilised either by DNAse I or by DNAse II. The data obtained are compatible with an involvement of SH and SS groups in chromatin structure and function.
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Turell, Lucia, Ari Zeida, and Madia Trujillo. "Mechanisms and consequences of protein cysteine oxidation: the role of the initial short-lived intermediates." Essays in Biochemistry 64, no. 1 (January 10, 2020): 55–66. http://dx.doi.org/10.1042/ebc20190053.

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Abstract Thiol groups in protein cysteine (Cys) residues can undergo one- and two-electron oxidation reactions leading to the formation of thiyl radicals or sulfenic acids, respectively. In this mini-review we summarize the mechanisms and kinetics of the formation of these species by biologically relevant oxidants. Most of the latter react with the deprotonated form of the thiol. Since the pKa of the thiols in protein cysteines are usually close to physiological pH, the thermodynamics and the kinetics of their oxidation in vivo are affected by the acidity of the thiol. Moreover, the protein microenvironment has pronounced effects on cysteine residue reactivity, which in the case of the oxidation mediated by hydroperoxides, is known to confer specificity to particular protein cysteines. Despite their elusive nature, both thiyl radicals and sulfenic acids are involved in the catalytic mechanism of several enzymes and in the redox regulation of protein function and/or signaling pathways. They are usually short-lived species that undergo further reactions that converge in the formation of different stable products, resulting in several post-translational modifications of the protein. Some of these can be reversed through the action of specific cellular reduction systems. Others damage the proteins irreversibly, and can make them more prone to aggregation or degradation.
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Pöther, Dierk-Christoph, Manuel Liebeke, Falko Hochgräfe, Haike Antelmann, Dörte Becher, Michael Lalk, Ulrike Lindequist, et al. "Diamide Triggers Mainly S Thiolations in the Cytoplasmic Proteomes of Bacillus subtilis and Staphylococcus aureus." Journal of Bacteriology 191, no. 24 (October 16, 2009): 7520–30. http://dx.doi.org/10.1128/jb.00937-09.

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ABSTRACT Glutathione constitutes a key player in the thiol redox buffer in many organisms. However, the gram-positive bacteria Bacillus subtilis and Staphylococcus aureus lack this low-molecular-weight thiol. Recently, we identified S-cysteinylated proteins in B. subtilis after treatment of cells with the disulfide-generating electrophile diamide. S cysteinylation is thought to protect protein thiols against irreversible oxidation to sulfinic and sulfonic acids. Here we show that S thiolation occurs also in S. aureus proteins after exposure to diamide. We further analyzed the formation of inter- and intramolecular disulfide bonds in cytoplasmic proteins using diagonal nonreducing/reducing sodium dodecyl sulfate gel electrophoresis. However, only a few proteins were identified that form inter- or intramolecular disulfide bonds under control and diamide stress conditions in B. subtilis and S. aureus. Depletion of the cysteine pool was concomitantly measured in B. subtilis using a metabolomics approach. Thus, the majority of reversible thiol modifications that were previously detected by two-dimensional gel fluorescence-based thiol modification assay are most likely based on S thiolations. Finally, we found that a glutathione-producing B. subtilis strain which expresses the Listeria monocytogenes gshF gene did not show enhanced oxidative stress resistance compared to the wild type.
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Tong, Ka-Chung, Chun-Nam Lok, Pui-Ki Wan, Di Hu, Yi Man Eva Fung, Xiao-Yong Chang, Song Huang, Haibo Jiang, and Chi-Ming Che. "An anticancer gold(III)-activated porphyrin scaffold that covalently modifies protein cysteine thiols." Proceedings of the National Academy of Sciences 117, no. 3 (January 2, 2020): 1321–29. http://dx.doi.org/10.1073/pnas.1915202117.

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Cysteine thiols of many cancer-associated proteins are attractive targets of anticancer agents. Herein, we unequivocally demonstrate a distinct thiol-targeting property of gold(III) mesoporphyrin IX dimethyl ester (AuMesoIX) and its anticancer activities. While the binding of cysteine thiols with metal complexes usually occurs via M–S bond formation, AuMesoIX is unique in that the meso-carbon atom of the porphyrin ring is activated by the gold(III) ion to undergo nucleophilic aromatic substitution with thiols. AuMesoIX was shown to modify reactive cysteine residues and inhibit the activities of anticancer protein targets including thioredoxin, peroxiredoxin, and deubiquitinases. Treatment of cancer cells with AuMesoIX resulted in the formation of gold-bound sulfur-rich protein aggregates, oxidative stress-mediated cytotoxicity, and accumulation of ubiquitinated proteins. Importantly, AuMesoIX exhibited effective antitumor activity in mice. Our study has uncovered a gold(III)-induced ligand scaffold reactivity for thiol targeting that can be exploited for anticancer applications.
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Mu, Huiying, Koji Miki, Takuya Kubo, Koji Otsuka, and Kouichi Ohe. "Substituted meso-vinyl-BODIPY as thiol-selective fluorogenic probes for sensing unfolded proteins in the endoplasmic reticulum." Chemical Communications 57, no. 14 (2021): 1818–21. http://dx.doi.org/10.1039/d0cc08160d.

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Thiol-selective probes based on BODIPY scaffold were developed for sensing small-molecule thiols and unfolded proteins. The good organelle specificity of probe enables its utility for reporting the protein unfolding under ER stress in living cells.
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Deponte, Marcel, and Christopher Horst Lillig. "Enzymatic control of cysteinyl thiol switches in proteins." Biological Chemistry 396, no. 5 (May 1, 2015): 401–13. http://dx.doi.org/10.1515/hsz-2014-0280.

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Abstract The spatiotemporal modification of specific cysteinyl residues in proteins has emerged as a novel concept in signal transduction. Such modifications alter the redox state of the cysteinyl thiol group, with implications for the structure and biological function of the protein. Regulatory cysteines are therefore classified as ‘thiol switches’. In this review we emphasize the relevance of enzymes for specific and efficient redox sensing, evaluate prerequisites and general properties of redox switches, and highlight mechanistic principles for toggling thiol switches. Moreover, we provide an overview of potential mechanisms for the initial formation of regulatory disulfide bonds. In brief, we address the three basic questions (i) what defines a thiol switch, (ii) which parameters confer signal specificity, and (iii) how are thiol switches oxidized?
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Cabrillana, María Eugenia, María de los Ángeles Monclus, Tania Estefania Sáez Lancellotti, Paola Vanina Boarelli, Amanda Edith Vincenti, Miguel Matias Fornés, Eduardo Alfredo Sanabria, and Miguel Walter Fornés. "Thiols of flagellar proteins are essential for progressive motility in human spermatozoa." Reproduction, Fertility and Development 29, no. 7 (2017): 1435. http://dx.doi.org/10.1071/rd16225.

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Male infertility is a disorder of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse. The presence of low-motile or immotile spermatozoa is one of many causes of infertility; however, this observation provides little or no information regarding the pathogenesis of the malfunction. Good sperm motility depends on correct assembly of the sperm tail in the testis and efficient maturation during epididymal transit. Thiols of flagellar proteins, such as outer dense fibre protein 1 (ODF1), are oxidised to form disulfides during epididymal transit and the spermatozoa become motile. This study was designed to determine how oxidative changes in protein thiol status affect progressive motility in human spermatozoa. Monobromobimane (mBBr) was used as a specific thiol marker and disruptor of sperm progressive motility. When mBBr was blocked by dithiothreitol it did not promote motility changes. The analysis of mBBr-treated spermatozoa revealed a reduction of progressive motility and an increased number of spermatozoa with non-progressive motility without affecting ATP production. Laser confocal microscopy and western blot analysis showed that one of the mBBr-positive proteins reacted with an antibody to ODF1. Monobromobimane fluorescence intensity of the sperm tail was lower in normozoospermic than asthenozoospermic men, suggesting that thiol oxidation in spermatozoa of asthenozoospermic men is incomplete. Our findings indicate that mBBr affects the thiol status of ODF1 in human spermatozoa and interferes with progressive motility.
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Peng, An An, Jin Lan Xia, Hong Chang Liu, Wei Zhu, Rui Yong Zhang, Cheng Gui Zhang, and Zhen Yuan Nie. "Thiol-Rich Proteins Play Important Role in Adhesion and Sulfur Oxidation Process of Acidithiobacillus ferroxidans." Advanced Materials Research 825 (October 2013): 137–40. http://dx.doi.org/10.4028/www.scientific.net/amr.825.137.

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The proteomics of the extracellular proteins (EPs), outer membrane proteins (OMPs) and the periplasmic proteins (PPs) ofAcidithiobacillus ferrooxidansATCC 23270 grown on Fe2+and S0substrates, respectively, were comparatively studied. 39 expression up-regulated proteins (including 13 EPs, 9 OMPs and 17 PPs) were identified and 70% of them contain cysteine residues in sequence. Some of the selected proteins especially the EPs contain abundant of the cysteine residues and one or more-CXXC-functional motifs. The thiol groups on theAt. ferrooxidanscell surface were selectively marked by Ca2+and SR-μ-XRF mappingin situobservation revealed that the number of thiols on the surface of the cells grown on S0was about five times as that grown on Fe2+substrate. When 0.01 g/L surfactant Tween-80 was added in the S0culture medium, the adsorption and activation related EPs were down-regulated and the sulfur metabolism related proteins was up-regulated. The same phenomenon was observed when the cells were grown on the more easily adhesion sulfur allotrope μ-S. It indicates that the thiol-rich proteins played important roles in adhesion and sulfur oxidation process ofAt. ferrooxidans.
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Dissertations / Theses on the topic "Proteins thiol"

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Le, Min. "Protein coimmobilization: Reactions of vicinal thiol groups of proteins /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487946776021788.

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Kantner, Terrence. "Bioconjugation strategies through thiol-alkylation of peptides and proteins." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675737.

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Bioconjugation chemistry generally refers to the covalent derivatisation of biomolecules. Derivatisation of cysteine’s thiol of peptides and proteins is a common method in bioconjugation chemistry as the thiolate is an excellent nucleophile in aqueous conditions. The propensity for thiols to oxidise in an aqueous environment necessitates the need for a disulfide reduction step prior to the addition of ligands derivatised with thiol alkylating linkers. Disulfide reducing agents such as tris(2-carboxyethyl)phosphine (TCEP) and tris(3-hydroxypropyl)phosphine (THPP) are disulfide reducing agents that are often marketed as being non-reactive with thiol alkylating reagents. The reaction of TCEP and THPP with thiol alkylation linkers was therefore investigated. Characterisation of reaction products and mechanistic studies revealed that TCEP and THPP both react with thiol alkylation reagents. A novel protocol was, therefore, developed utilising the Staudinger reaction to oxidise excess TCEP and THPP prior to the addition of thiol alkylating reagents. The protocol offers a simple “one-pot” method for effecting conjugate production via thiol alkylation, without the need for an intermediate purification step for the removal of excess disulfide reducing agents. 4-Vinyl pyridine (4-VP) derivatives were developed and explored as an alternative Michael acceptor class for thiol alkylation of peptides and proteins. The 4-VP derivatives exhibited high reactivity and specificity for thiol alkylation between pH = 7 and pH = 8. A selection of 4-VP linkers were subsequently functionalised with either carbohydrates or polyethylene glycol (PEG) and successfully utilised to produce peptide or protein conjugates via thiol alkylation reactions.
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Pennisi, Manuela. "Redox proteomics, thiol homeostasis and neurophysiologicla correlations in aging and neurodegeneration." Doctoral thesis, Università di Catania, 2014. http://hdl.handle.net/10761/1533.

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The terms "aging" and "neurodegeneration" are often used in a broad and generalized manner. Actually, they are particularly complex and multifaceted processes, involving different biochemical systems. Increasing evidence supports the notion that reduction of cellular expression and activity of antioxidant proteins and the resulting increase of oxidative stress are fundamental causes in the aging processes and neurodegenerative diseases. Within the frame of free radical hypothesis of aging, several lines of evidence suggest that accumulation of oxidative molecular damage is a causal factor in senescence. It is also increasingly evident that the mitochondrial genome may play a key role in aging and neurodegenerative diseases. Mitochondrial dysfunction is characteristic of several neurodegenerative disorders, and evidence for mitochondria being a site of damage in neurodegenerative disorders is partially based on decreases in respiratory chain complex activities in Parkinson s disease (PD), Alzheimer s disease (AD), and Huntington s disease (HD). Such defects in respiratory complex activities, possibly associated with oxidant/antioxidant balance perturbation, are thought to underlie defects in energy metabolism and induce cellular degeneration. Efficient functioning of mantainance and repair process seems to be crucial for both survival and physical quality of life. This is accomplished by a complex network of the so-called "longevity assurance processes", which are composed of several genes, termed vitagenes. Among these, heat shock proteins, also known as stress proteins and molecular chaperones, are highly conserved proteins for the preservation and repair of the correct conformation of cellular macromolecules, such as proteins, RNAs and DNA. Chaperone-buffered silent mutations may be activated during the aging process and lead to the phenotypic exposure of previously hidden features and contribute to the onset of multigenic diseases, such as age-related disorders, atherosclerosis and cancer. Recent studies have shown that the heat-shock response contributes to establishing a cytoprotective state in a wide variety of human diseases, including ischemia and reperfusion damage, inflammation, metabolic disorders, cancer, infection, trauma, and aging. The major neurodegenerative diseases, Alzheimer s disease (AD), Parkinson s disease (PD), amyotrophic lateral sclerosis (ALS), Huntington s disease (HD), and Friedreich s ataxia (FA), are all associated with the presence of abnormal. Given the broad cytoprotective properties of the heat-shock response, there is now strong interest in discovering and developing pharmacological agents capable of inducing the heat-shock response. These findings have opened up new perspectives in medicine and pharmacology, as molecules inducing this defense mechanism appear to be possible candidates for novel cytoprotective strategies. Particularly, modulation of endogenous cellular defense mechanisms such as the heat-shock response, and the proteasomal system, through nutritional antioxidants or pharmacological compounds may represent an innovative approach to therapeutic intervention in diseases causing tissue damage, such as neurodegeneration. Moreover, by maintaining or recovering the activity of vitagenes, it would be possible to delay the aging process and decrease the occurrence of age-related diseases with resulting prolongation of a healthy life span.
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Gough, Jonathan David Lees Watson J. "Aromatic thiol based redox buffers increasing the folding rates of disulfide containing proteins /." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.

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Hall, Michael. "The chloroplast lumen : New insights into thiol redox regulation and functions of lumenal proteins." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-58423.

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In higher plants oxygenic photosynthesis primarily takes place in the chloroplasts of leaves. Within the chloroplasts is an intricate membrane system, the thylakoid membrane, which is the site of light harvesting and photosynthetic electron transport. Enclosed by this membrane is the lumen space, which initially was believed to only contain a few proteins, but now is known to house a distinct set of >50 proteins, many for which there is still no proposed function. The work presented in this thesis is focused on understanding the functions of the proteins in the lumen space. Using proteomic methods, we investigated first the regulation of lumenal proteins by light and secondly by dithiol-disulphide exchange, mediated by the disulphide reductase protein thioredoxin. We furthermore performed structural and functional studies of the lumenal pentapeptide repeat proteins and of the PsbP-domain protein PPD6. When studying the diurnal expression pattern of the lumen proteins, using difference gel electrophoresis, we observed an increased abundance of fifteen lumen protein in light-adapted Arabidopsis thaliana plants. Among these proteins were subunits of the oxygen evolving complex, plastocyanin and proteins of unknown function. In our analysis of putative lumenal targets of thioredoxin, we identified nineteen proteins, constituting more than 40 % of the lumen proteins observable by our methods. A subset of these putative target proteins were selected for further studies, including structure determination by x-ray crystallography. The crystal structure of the pentapeptide repeat protein TL15 was solved to 1.3 Å resolution and further biochemical characterization suggested that it may function as a novel type of redox regulated molecular chaperone in the lumen. PPD6, a member of the PsbP-family of proteins, which is unique in that it possesses a conserved disulphide bond not found in any other PsbP-family protein, was also expressed, purified and crystallized. A preliminary x-ray analysis suggests that PPD6 exists as a dimer in the crystalline state and binds zinc ions. The high representation of targets of thioredoxin among the lumen proteins, along with the characterization of the pentapeptide repeat protein family, implies that dithiol-disulphide exchange reactions play an important role in the thylakoid lumen of higher plants, regulating processes such as photoprotection, protein turnover and protein folding.
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Lui, James Kwok Ching. "A fluorescent labelling technique to detect changes in the thiol redox state of proteins following mild oxidative stress." University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0056.

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There is increasing evidence that hydrogen peroxide (H2O2) can act as a signalling molecule capable of modulating a variety of biochemical and genetic systems. Using Jurkat T-lymphocytes, this study initially investigated the involvement of H2O2 in the activation of a specific signalling protein extracellular signal-regulated protein kinase (ERK). It was found that as a result of H2O2 treatment, mitochondrial complex activities decreased which led to subsequent increase of mitochondrial reactive oxygen species (ROS) production. The increase of ROS resulted in higher cellular H2O2 as well as increased ERK activation. This study demonstrated that in an oxidative stress setting, H2O2 production from the mitochondria was an essential component in maintaining the activation of a signalling protein. One way in which H2O2 could influence protein function is by the oxidation of susceptible thiol groups of cysteine residues. To further understand the variety of signalling pathways that H2O2 may be involved in, an improved proteomics technique was developed to globally identify proteins with susceptible thiol groups. The
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Zhang, Yun. "Mass Spectrometric Analysis of Thiol Proteins/Peptides Following Selenamide Derivatization And Electrolytic Reduction of Disulfide Bonds." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1347395762.

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Hameed, Rana Majeed. "The application of aqueous two phase systems to the analysis of protein isoforms of importance in clinical biochemistry and biopharmaceutical production." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/14452.

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Aqueous Phase Partitioning has a long history of applications to the analytical characterisation of biomolecules. However process applications have attracted the most interest in biotechnology where it has become widely recognized as a cost-effective technique. The main aim of this work was to explore the proposition that partition in Aqueous Two Phase Systems (ATPS) can be used as an analytical tool to detect protein isoforms and to assess the applicability of the method in clinical assays and for quality control in bioprocessing through examination of several analytical problems. The work also examined the development of automated methods of system preparation and sampling techniques to determine the partition coefficient in ATPS. The study demonstrated that the geometrical form of the phase diagram co-existence curve was of crucial importance since this directly affected the accuracy with which systems of defined Tie Line Length and Mass Ratio could be constructed. The TLL %Bias (accuracy) of a theoretical system range in the PEG1000-(NH4)2SO4 system at shorter TLL (12.2) was in the range +80.6% to -100% while at a longer TLL (53.1) the %Bias (accuracy) was reduced to +0.1% to -1.9%. At the same time the MR %Bias (accuracy) at shorter TLL (12.2) was in the range +59.5% to -21.3% while at the longer TLL (53.1) this was reduced to +2.7% to -2.6%. By contrast in the PEG8000-Dextran500 system the TLL %Bias (accuracy) at shorter TLL (13.1) was in the range +3.7% to -4.12%, while at a longer TLL (31.1) the range was +0.74% to -0.67%. The MR %Bias (accuracy) at the shorter TLL (13.1) was in the range +3.6% to -3% while at the longer TLL (31.1) the range was +1.1% to -1.4%. This illustrated that it is more difficult to work with a high degree of accuracy (e.g. %Bias <5%) close to the critical point in PEG-salt systems than in PEG-dextran systems. Two different approaches were taken to examine analytical phase partitioning. In the first approach the structure of the isoforms of a model protein (ovalbumin) were altered enzymatically. Analytical methods involving Strong Anion-Exchange chromatography were developed and applied to the separation of the ovalbumin isoforms. Removal of the phosphorylated groups (dephosphorylation of ovalbumin) was undertaken using alkaline phosphatase and de-glycosylation was attempted using neuraminidase and Endo-glycosidase F. However, both enzymatic approaches to deglycosylation were unsuccessful. Dephosphorylated isoforms were successfully produced and characterised. After partitioning in ATPS a clear difference was demonstrated between the behaviour of the native and dephosphorylated forms of ovalbumin. The mean % recovery in a PEG-salt ATPS was 99.8% (± 3.59) for the naive protein and 75.6% (± 4.03) for the dephosphorylated form. On the other hand, in a PEG3350-Dextran500 system, where solubility was maintained, a significant difference in the partition coefficient (K) of native and dephosphorylated ovalbumin was found. K for native ovalbumin was 0.85 while the partition coefficient of the dephosphorylated ovalbumin was 0.61. Analysis of covariance (ANCOVA) indicated that the regression coefficients of the respective partition isotherms were significantly different (p value < 0.05). In a second approach to examine analytical phase partitioning, chemical modification of a specific target surface amino acid of another model protein (serum albumin) was used to determine the degree of conjugation of the protein and also to determine its oxidative state. The method examined the reactivity of a free surface thiol to a wide range of labels ( (a) 2-methylsulfonyl-5-phenyl -1,3,4 oxidiazole reagent, (b) N-Ethylmaleimide (NEM) reagent, (c) 5, 5’-dithiobis (2-nitrobenzoate)(DTNB) (Ellman’s reagent), (d) N-pyrenylmaleimide (NPM) reagent, (e) Fluorescein-5-maleimide (F-5-M) Reagent). Only DTNB was found to modify the surface free thiol of serum albumin in a highly specific and quantitative manner. In the course of the development of a partitioning assay for surface free thiols of serum albumin significant oxidative properties were found to be associated with poly(ethylene glycol) PEG solutions and several attempts were made to find an oxidatively safe partitioning system by including antioxidants and by removal of contaminants by freeze drying. PEG3350-Dextran500 was found to provide an oxidatively safe environment for the development of a partitioning assay for the determination of albumin free thiols. A phase partitioning assay system capable of quantitatively resolving protein associated free thiols and low molecular weight thiols from a mixture of the two was developed. Correlation coefficients (R2) for the regression of experimentally determined protein free thiols in the presence of different levels of added LMW free thiol on the known addition of protein ranged from 0.77 to 0.83. The results demonstrated that the assay could quantify and distinguish both types of thiol in a simple two-step procedure.
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Safazadeh, Haghighi Leila. "DESIGN OF HIGHLY STABLE LOW-DENSITY SELF-ASSEMBLED MONOLAYERS USING THIOL-YNE CLICK REACTION FOR THE STUDY OF PROTEIN-SURFACE INTERACTIONS." UKnowledge, 2016. http://uknowledge.uky.edu/cme_etds/61.

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Protein adsorption on solid surfaces is a common yet complicated phenomenon that is not fully understood. Self-assembled monolayers have been utilized in many studies, as well-defined model systems for studying protein-surface interactions in the atomic level. Various strategies, including the use of single component SAMs[1, 2], combinations of long and short alkanethiolates with methyl- and hydroxyl- terminal groups[3, 4], and using mixtures of alkanethiolates with similar chain length and varying terminal functional group [5] have been used to effectively control the surface wettability and determine the effect of surface composition and wettability on protein adsorption. In this dissertation we report key new findings on the effect of surface density of functional groups on protein adsorption phenomenon. In The first phase of this research, we developed a novel approach for preparation of low-density self-assembled monolayers(LD-SAMs) on gold surfaces, based on radical-initiated thiol-yne click chemistry. This approach provides exceptional adsorbate stability and conformational freedom of interfacial functional groups, and is readily adapted for low-density monolayers of varied functionality. The resulting monolayers have two distinct phases: a highly crystalline head phase adjacent to the gold substrate, and a reduced density tail phase, which is in contact with the environment. First, we investigated the feasibility of the proposed chemistry in solution-phase. In this approach, we synthesized “Y” shaped carboxylate-terminated thiol adsorbates via radical-initiated thiol-yne reaction. The LD-SAMs were then prepared through immersion of gold substrates into the solution of synthesized adsorbate molecules in hexane. The chemical structuring and electrochemical properties of resultant LD-SAMs were analyzed and compared with those of analogous traditional well-packed monolayers, using techniques such as Fourier transform infrared spectroscopy, ellipsometry, electrochemical impedance spectroscopy, reductive desorption, and contact angle goniometry. Characterization results indicated that resulting LD-SAMs have a lower average crystallinity, and higher electrochemical stability compared to well-packed monolayers. In addition, using a three-electrode system, we were able to show a reversible change in LD-SAM surface wettability, in response to an applied voltage. This remodeling capacity confirms the low density of the surface region of LD-SAM coatings. The second area of work was focused on using the developed chemistry in solid-phase. The solid-phase approach minimized the required synthesis steps in solution-phase method, and used the photo-initiated thiol-yne click-reaction for grafting of acid-terminated alkynes to thiol-terminated monolayers on a gold substrate to create similar LD-SAMs as what were prepared through solution-phase process. We characterized the resulting monolayers and compared them to analogous well-packed SAMs and the also low-density monolayers prepared through the solution phase approach. The results confirmed the proposed two-phase structure, with a well-packed phase head phase and a loosely-packed tail phase. In addition, the electrochemical studies, indicated that the resultant monolayers were less stable than the monolayers prepared via solution-phase, but they are yet significantly more stable than typical well-packed monolayers. The less stability of these monolayers were attributed to the partial desorption of adsorbates from the gold substrate due to UV irradiation during the grafting process. Building on the established chemistry, we studied the effect of lateral packing density of functional groups in a monolayer on the adsorption of Bovine serum albumin protein. we used surface plasmon resonance spectroscopy (SPR) and spectroscopic ellipsometry, to evaluate BSA adsorption on carboxylate‑, hydroxyl-, or alkyl- terminated LD-SAMs. It was found that for the LD-SAMs, the magnitude of protein adsorption is consistently higher than that of a pure component, well-packed SAM for all functionalities studied. In addition, it was seen that the magnitude of BSA adsorption the LD-SAMs, was consistently higher than that of a pure component, well-packed SAM for all functionalities studied. The difference of protein adsorption on LD-SAMs and SAMs can not be associated to difference in lateral packing density, unless we eliminate the impact of other contributing factors in protein adsorption such as surface energy. In order to better understand the impact of packing density on protein-surface interactions, we prepared the mixed SAMs of (carboxylate/alkyl) and (hydroxyl/alkyl) with matching surface energy as the carboxylate and hydroxyl terminated LD-SAMs. It was found that the energy-matched mixed SAMs of carboxylate and hydroxyl functionality adsorbed more protein than the LD-SAMs. However, an opposite trend was seen for the alkyl surfaces, where surface energies are comparable for LD-SAMs and pure component SAMs, indicating that BSA proteins have higher affinity for methyl- terminated LD-SAMs than well-packed SAMs.
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Kade, Ige Joseph. "Interaction of organodiselenides with sulphydryl groups at the active sites of some thiol containing proteins - in vitro and in vivo mechanistic studies in mammalian models of diabetes." Universidade Federal de Santa Maria, 2008. http://repositorio.ufsm.br/handle/1/4398.

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The present study sought to compare the in vitro antioxidant potentials of a newly synthesized organodiselenide, dicholesteroyl diselenide (DCDS) and diphenyl diselenide (DPDS) and their possible interactions with some thiol containing enzymes in different tissues from mammalian system. In addition, the potency of DPDS as antioxidant and antihyperglycaemic agents, and its interaction with thiol containing proteins in various mammalian tissues and organs (hepatic, renal and spleenic and more importantly cerebral tissues) were evaluated in animal models of streptozotocin induced diabetic rats. The in vitro results show that DPDS exhibited a higher glutathione-peroxidase mimetic activity as well as increased ability to oxidize both mono- and di- thiols than DCDS. In addition, while DPDS inhibited thiobarbituric acid reactive substances (TBARS) and protein carbonyls formations in both cerebral and hepatic tissues, induced by either iron (II) or SNP, DCDS exhibited a prooxidant effect in both cerebral and hepatic tissues when iron (II) serves as the prooxidant, However, when TBARS was induced by SNP, DCDS slightly modify TBARS formation in both hepatic and cerebral tissues. Also the activities of cerebral and hepatic delata aminolevulinic acid dehydratase (ð-ALA-D), cerebral Na+/K+- ATPase were significantly inhibited by DPDS and only weakly inhibited by the DCDS. Further studies reveal that the inhibition caused by organodiselenides (in this case, DPDS) on Na+/K+-ATPase activity likely involves the modification of the thiol groups at the ATP binding site of the enzyme. Similarly, different isoforms of lactate dehydrogenase (LDH) were significantly inhibited by both DPDS and DCDS in vitro. Likewise, we observed that the in vitro inhibition of different isoforms of lactate dehydrogenase by DCDS and DPDS likely involves the modification of the -SH groups at the NAD+ binding site of the enzyme. Oral administration of DPDS dissolved in soya bean oil administered to streptozotocin induced diabetes in male albino rats shows that there was significant reduction in blood glucose levels accompanied by a marked reduction of glycated proteins in streptozotocin induced diabetic rats treated with DPDS in relation to untreated streptozotocin induced diabetic. In addition, DPDS was able to significantly ameliorate the levels of Vitamin C and GSH (liver, kidney and spleen), which were decreased in streptozotocin treated rats. Similarly, treatment with DPDS was able to markedly abolish the increase levels of TBARS that were observed in STZ diabetes group. Finally, the inhibition of both ð-ALA-D and some isoforms of LDH caused by hyperglycaemia were prevented by DPDS. We also observed that although streptozotocin evoke a significant diminution on brain s antioxidant status and activity of Na+/K+-ATPase, but the activity of acetylcholineesterase and glutamate uptake and release were not altered. However, DPDS was able to markedly restore the observed imbalance in antioxidant status and sodium pump. Finally, we conclude that organodiselenides are promising antioxidant remedy in the management of diseases caused by oxidative stress. However, their toxicity involves an interaction with thiols on proteins and this study has further demonstrated that the sulphydryl groups in question are critical to the normal function of the protein or enzymes. Most likely, these -SH are associated with thiols at the substrate binding (active site) sites of the enzymes. Interestingly, pharmacological doses of organodiselenides 3mg/kg bw for the study on diabetes do not present any observed toxicity.
O presente estudo quis comparar os potenciais antioxidants in vitro de organoselênios novamente sintetizados, diseleneto dicolesterol e diseleneto de difenila e suas possíveis interações com algumas enzimas contendo tióis em diferentes tecidos de mamíferos. Além disso, o potencial de DPDS como agente antioxidante e antihiperglicêmico, e sua interação com proteínas contendo tióis em vários tecidos e órgãos de mamíferos (hepático, renal, esplênico e, mais importante, tecido cerebral) foram avaliados em modelos animais de streptozotocina induzindo diabetes em ratos. Os resultados in vitro mostram que DPDS exibiu uma maior atividade mimética da glutationa peroxidase bem como aumentada habilidade para oxidar mono e di-tióis que DPDS. Além disso, enquanto o DPDS inibiu substâncias reativas ao ácido tiobarbitpúrico (TBARS) e formação de proteínas carboniladas em tecidos cerebral e hepático, induzidas por ferro(II) ou SNP, DCDS exibiu um efeito pró-oxidante em cérebro e tecido hepático quando ferro(II) serviu como próoxidante, porém, quando TBARS foi induzido por SNP, DCDS modificou a formação de TBARS tanto em tecido cerebral como hepático. Também, as atividades da deltaaminolevulinato desidratase (ð-ALA-D) cerebral e hepática e Na+/K+-ATPase cerebral foram significativamente inibidas por DPDS e somente fracamente inibida por DCDS. Mas estudos revelam que a inibição causada por organodiselenetos (neste caso, DPDS) na atividade da Na+/K+-ATPase envolve a modificação de grupos tiólicos ligados ao sítio ATP da enzima. Similarmente, diferentes isoformas da lactato desidrogenase (LDH) foram significativamente inibidas por DPDS e DCDS in vitro. nós observamos que a inibição in vitro de diferentes isoformas da LDH por DCDS e DPDS envolve a modificação de grupos SH no sítio ligante NAD+ da enzima. a administração oral de DPDS dissolvido em óleo soya administrado a ratos albino machos com diabetes induzida por streptozotocina mostrou que houve uma redução significante nos níveis de glicose sanguínea acompanhada por uma marcada redução nas proteínas glicadas em ratos diabéticos induzidos com streptozitocina tratados com DPDS em relação aos não diabéticos. Além disso, DPDS melhorou significativamente os níveis de vitamina C e GSH (fígado, rim e baço), que foram diminuídos em ratos tratados com streptozotocina. Similarmente, tratamento com DPDS marcadamente aboliu os níveis elevados de TBARS que foram observados no grupo diabético. Finalmente, a inibição da ð-ALA-D e algumas isoformas da LDH causada pela hiperglicemia foram prevenidas por DPDS. Nós também observamos que STZ provocou uma significante diminuição no status antioxidante do cérebro e atividade da Na+/K+- ATPase, mas a atividade da acetilcolinesterase e captação e liberação de glutamato não foram alteradas. Porém, DPDS marcadamente restaurou o desequilíbrio observado no status antioxidante e bomba de sódio. Finalmente, nós concluímos que organoselenetos são remédios antioxidantes promissores no manejo de doenças causadas por estresse oxidativo. Porém, sua toxicidade envolve uma interação com tióis em proteínas e este estudo demonstrou que os grupos sulfidril em questão são críticos para a função normal de enzimas e proteínas. Estes SH são associados com tióis dos sítios de ligação do substrato (sítio ativo) de enzimas. interessantemente, doses farmacológicas de organodiselenetos (3mg/kg para o estudo de diabetes) não apresentou nenhuma toxicidade observada.
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Books on the topic "Proteins thiol"

1

Kosuri, Pallav. Mechanochemical Methods for Single Molecule Biochemistry and Studies of Thiol-Disulfide Exchange in Proteins. [New York, N.Y.?]: [publisher not identified], 2012.

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service), ScienceDirect (Online, ed. Thiol redox transitions in cell signaling: Cellular localization and signaling. San Diego, Calif: Elsevier, 2010.

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1942-, Sies H., and Packer Lester, eds. Protein sensors and reactive oxygen species. San Diego, Calif: Academic Press, 2002.

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Murricane, Christopher. Correlation between ribosome breakdown and activity of a lysosomal thiol proteinase in tetrahymena pyriformis. Birmingham: University of Birmingham, 1988.

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Principe, Paola Domenica Luiga. Quantitative studies of cellular protein thiol groups in relation to the growth behavior of rat livercell lines: Comparative estimations by computer microdensitometry, biochemistry and flow cytometry. Uxbridge: Brunel University, 1988.

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Protein Sensors and Reactive Oxygen Species - Part B: Thiol Enzymes and Proteins. Elsevier, 2002. http://dx.doi.org/10.1016/s0076-6879(00)x0020-1.

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Packer, Lester, and Helmut Sies. Protein Sensors and Reactive Oxygen Species, Part B: Thiol Enzymes and Proteins Pt. B. Elsevier Science & Technology Books, 2002.

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(Editor), Helmut Sies, and Lester Packer (Editor), eds. Methods in Enzymology, Volume 348: Protein Sensors and Reactive Oxygen Species, Part B: Thiol Enzymes and Proteins (Methods in Enzymology). Academic Press, 2002.

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(Editor), Helmut Sies, and Lester Packer (Editor), eds. Methods in Enzymology, Volume 348: Protein Sensors and Reactive Oxygen Species, Part B: Thiol Enzymes and Proteins (Methods in Enzymology). Academic Press, 2002.

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Thiol Redox Transitions in Cell Signaling Pt. A,Vol.473: Chemistry and Biochemistry of Low Molecular Weight and Protein Thiols. Elsevier Science & Technology Books, 2010.

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Book chapters on the topic "Proteins thiol"

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Buxbaum, Engelbert. "Thiol and Disulphide Reactive Reagents." In Biophysical Chemistry of Proteins, 205–7. Boston, MA: Springer US, 2010. http://dx.doi.org/10.1007/978-1-4419-7251-4_20.

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Ford, Amy E., and Kevin A. Morano. "Thiol-Based Redox Signaling: Impacts on Molecular Chaperones and Cellular Proteostasis." In Heat Shock Proteins, 3–22. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-03952-3_1.

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Cristian, Lidia, and Yao Zhang. "Use of Thiol-Disulfide Exchange Method to Study Transmembrane Peptide Association in Membrane Environments." In Membrane Proteins, 3–18. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-583-5_1.

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Moan, Natacha, Frédérique Tacnet, and Michel B. Toledano. "Protein-Thiol Oxidation, From Single Proteins to Proteome-Wide Analyses." In Redox-Mediated Signal Transduction, 175–92. Totowa, NJ: Humana Press, 2008. http://dx.doi.org/10.1007/978-1-59745-129-1_13.

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Eckels, Edward C., Daniel J. Echelman, Jaime Andrés Rivas-Pardo, and Julio M. Fernández. "CHAPTER 1.3. Real-time Detection of Thiol Chemistry in Single Proteins." In Oxidative Folding of Proteins, 52–80. Cambridge: Royal Society of Chemistry, 2018. http://dx.doi.org/10.1039/9781788013253-00052.

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Gilbert, Hiram F. "Thiol/disulfide exchange and redox potentials of proteins." In Bioelectrochemistry of Biomacromolecules, 256–324. Basel: Birkhäuser Basel, 1997. http://dx.doi.org/10.1007/978-3-0348-9179-0_5.

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Palacio-Castañeda, Valentina, Roland Brock, and Wouter P. R. Verdurmen. "Generation of Protein-Phosphorodiamidate Morpholino Oligomer Conjugates for Efficient Cellular Delivery via Anthrax Protective Antigen." In Methods in Molecular Biology, 129–41. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2010-6_8.

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AbstractPhosphorodiamidate morpholino oligomers (PMOs) offer great promise as therapeutic agents for translation blocking or splice modulation due to their high stability and affinity for target sequences. However, in spite of their neutral charge as compared to natural oligonucleotides or phosphorothioate analogs, they still show little permeability for cellular membranes, highlighting the need for effective cytosolic delivery strategies. In addition, the implementation of strategies for efficient cellular targeting is highly desirable to minimize side effects and maximize the drug dose at its site of action. Anthrax toxin is a three-protein toxin of which the pore-forming protein anthrax protective antigen (PA) can be redirected to a receptor of choice and lethal factor (LF), one of the two substrate proteins, can be coupled to various cargoes for efficient cytosolic cargo delivery. In this protocol, we describe the steps to produce the proteins and protein conjugates required for cytosolic delivery of PMOs through the cation-selective pore generated by anthrax protective antigen. The method relies on the introduction of a unique cysteine at the C-terminal end of a truncated LF (aa 1–254), high-yield expression of the (truncated) toxin proteins in E. coli, functionalization of a PMO with a maleimide group and coupling of the maleimide-functionalized PMO to the unique cysteine on LF by maleimide-thiol conjugation chemistry. Through co-administration of PA with LF-PMO conjugates, an efficient cytosolic delivery of PMOs can be obtained.
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Solecka-Witulska, Barbara A., Christoph Weise, and Christoph Kannicht. "Mass Spectrometry-Based Method for Detection and Identification of Free Thiol Groups in Proteins." In Post-Translational Modification of Proteins, 179–89. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9055-9_12.

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Anelli, Tiziana, and Roberto Sitia. "CHAPTER 3.4. Mechanisms of Oxidative Protein Folding and Thiol-dependent Quality Control: Tales of Cysteines and Cystines." In Oxidative Folding of Proteins, 249–66. Cambridge: Royal Society of Chemistry, 2018. http://dx.doi.org/10.1039/9781788013253-00249.

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Cuddihy, Sarah L., James W. Baty, Kristin K. Brown, Christine C. Winterbourn, and Mark B. Hampton. "Proteomic Detection of Oxidized and Reduced Thiol Proteins in Cultured Cells." In Methods in Molecular Biology, 363–75. Totowa, NJ: Humana Press, 2009. http://dx.doi.org/10.1007/978-1-59745-281-6_23.

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Conference papers on the topic "Proteins thiol"

1

ADAMCZYK, MACIEJ, PHILLIP G. MATTINGLY, JEFFREY A. MOORE, and SUSHIL D. REGE. "THIOL-SPECIFIC ACRIDINIUM REAGENTS FOR LABELING PROTEINS AND NUCLEIC ACIDS." In Proceedings of the 11th International Symposium. WORLD SCIENTIFIC, 2001. http://dx.doi.org/10.1142/9789812811158_0082.

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Aparicio‐Bautista, Diana Ivette, Nora Andrea Gutiérrez‐Nájera, Jaime Arellanes‐Robledo, Verónica Rocío Vásquez‐Garzón, Mónica Noemí Jiménez‐García, Julio Isael Pérez‐Carreón, and Saúl Villa‐Treviño. "Abstract C16: Reactive oxygen species derivate of diethylnitrosamine metabolism participates in oxidation of thiol proteins." In Abstracts: First AACR International Conference on Frontiers in Basic Cancer Research--Oct 8–11, 2009; Boston MA. American Association for Cancer Research, 2009. http://dx.doi.org/10.1158/0008-5472.fbcr09-c16.

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verhallen, P. F. J., E. M. Bevers, P. Comfurius, W. M. A. Linkskens, and R. F. A. Zwaal. "CALPAIN-MEDIATED CYTOSKELETAL DEGRADATION CORRELATES WITH STIMULATION OF PLATELET PROCOAGULANT ACTIVITY." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642821.

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We have shown earlier that the negatively charged phospholipid phosphatidylserine (PS), which becomes translocated from the inner surface to the outer surface of the plasma membrane upon platelet activation, is responsible for platelet procoagulant activity. Studies with erythrocytes have suggested a role for cytoskeletal proteins in the regulation of transmembrane asymmetry of PS. The possibility that platelet cytoskeletal proteins are involved in the loss of transmembrane asymmetry of PS, was explored by correlative investigations of both platelet prooagulant activity and activity of calpain, an endogenous Ca 2+ -dependent thiol-protease, known to hydrolyze major cytoskeletal proteins (e.g.: filamin, talin, myosin). Platelet procoagulant activity was assayed by determination of the prothrombinase activity under conditions at which the catalytic PS-surface was rate-limiting. Calpain-activity was monitored by the appearance of known degradation products of major cytoskeletal proteins. The following results were obtained: (1) The ability of thrombin, collagen, collagen & thrombin, or the Ca -ionophore A23187 to stimulate platelet procoagulant activity closely correlated with their ability to stimulate platelet calpain-activity (2). Generation of platelet procoagulant activity upon platelet stimulation by collagen & thrombin or by A23187 exhibited a time course identical to the development of calpain-activity. In addition, the local anesthetics dibucaine and tetracaine, shown to gradually stimulate calpain activity, were able to generate platelet procoagulant activity with a similar time course. (3) Using a Ca2+ buffering system and A23187 to equilibrate intracellular- and extracellular free Ca2+ , it was found that the Ca2+ -response relationship of both platelet calpain- and pro-coagulant-activity was identical. From these findings we conclude that the degradation of cytoskeletal proteins destroys their putative interactions with PS, enabling this lipid to participate in transbilayer movement, leading to the formation of a procoagulant outer surface of the platelet.
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Sharifimehr, Shahrzad, Supratim Ghosh, and Ramaswami Sammynaiken. "Development of Protein–polyphenol Conjugates via Free Radical Grafting Method: Evaluation of Physicochemical and Functional Properties." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/bpzg5215.

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Lipid oxidation is a common phenomenon in emulsions that can be controlled by different techniques. Since proteins are beneficial emulsifiers but with low antioxidant ability, they are used in combination with an antioxidant compound such as polyphenols. Strong interaction between the protein and the polyphenol makes this combination more effective. In this study, soluble fraction of faba protein concentrate (FPC) was conjugated with tannic acid via the free radical grafting, and the structural and functional characteristics of the conjugates were determined in comparison with the mixture of the protein and tannic acid, and the pure protein. After dialysis, the amount of protein and polyphenol from the conjugated materials was significantly reduced, indicating that the unreacted peptides and polyphenol left the solutions. The reduction of the free amino and thiol groups in the protein specified the establishment of a strong interaction between the protein and tannic acid remaining in the solution. Moreover, the conjugate showed high ABTS, hydroxyl radical scavenging activity and ferric reducing power than the protein alone. As the purpose of making the conjugate was to be used as a multilayer film around the oil droplets, the film formation ability of the conjugates was investigated using Langmuir-Blodgett technique. Depending on the size of the trough and the nature of the compounds being used, the concentration and surface pressure required to form a strong film will vary. All samples showed an extended gas state of the film that changed abruptly and directly into a solid state below a critical surface area. Such LB film of the protein-tannic acid conjugate will be used to test its free radical scavenging ability so that its ability to prevent lipid oxidation in emulsions can be predicted.
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Wu, Haizhou, Jie Yin, and Mark Richards. "Inhibitory Mechanisms of Quercetin Against Hemoglobin-mediated Lipid Oxidation in Washed Muscle Model." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ituo9388.

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Lipid oxidation in fresh and further processed meat facilitates quality deterioration during storage, including loss of color, flavor, and in some cases nutritional value. Flavonoids are found ubiquitously in plants as a member of polyphenolic compounds and have received considerable attention for their antioxidant properties. Numerous studies have demonstrated that free radical scavenging and metal chelation could be the key factors responsible for the antioxidative activities of flavonols. In our previous work, a fraction isolated from cranberry juice powder was an effective inhibitor of lipid oxidation in mechanically separated turkey (MST) and washed cod muscle. The compound responsible for the inhibitory activity was then identified as quercetin. However, the mechanisms by which quercetin inhibits lipid oxidation due to heme proteins present in muscle foods has received little attention. With this background, we studied the antioxidant effect of quercetin on hemoglobin(Hb)-mediated lipid oxidation and the mechanisms involved in washed cod muscle model. Quercetin strongly inhibited Hb-mediated lipid oxidation in washed muscle. Quercetin showed effective hydroxyl radical scavenging ability similar to butylated hydroxytoluene (BHT). Quercetin reduced metHb resulting in formation of oxyHb. Bound quercetin decreased heme dissociation from metHb. Conversion to oxyHb and decreased heme dissociation represent routes to limit Hb-mediated lipid oxidation. Electrospray ionization mass spectrometry (ESI-MS) indicated one molecule of quercetin was covalently bound to Hb α-chain. Quercetin quinone docked 3.3 Å from the thiol of αCys(H15) but not near any other Cys residues of turkey Hb. At the docking site, hydrogen bonding between quercetin quinone and amino acids of α- and β-chain was demonstrated. This represents a path by which quercetin became covalently bound to α-chain. Molecular docking of heme proteins to polyphenols provides a template to better understand antioxidant interactions in muscle foods.
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Peyronel, Fernanda, David Pink, Gurpreet Matharoo, Iris Joye, Shajahan Razul, and Wei Cao. "Spontaneous aggregation of glutathione in aqueous solutions and the use of Ellman's procedure to detect thiol moieties." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/cyco6389.

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Ellman's procedure for detecting thiol moieties has been used to quantify the formation of disulfide bonds. The philosophy here is that DTNB used by Ellman will detect the development of oxidation as a function of time as per temporal decrease of the SH moieties. Recently (Lauwers et al 2016, Cao et al 2021) this technique was used to quantify the oxidation of cysteine and glutathione as function of time. It was reported that, at pH = 6.5, for all cases of cysteine and one case of glutathione studied, the number of thiols became zero in a finite time, tc. Using Smoluchowski equations (a) we pointed out that in milliQ water with cysteine molecules searching randomly to form disulfide bonds, we should find that tc → ∞, and (b) we proposed that cysteine molecules, carrying zero net charge at pH = 6.5, aggregated so that SH groups were ‘hidden’ in the interior thus preventing the detection of thiols by DTNB thus erroneously reporting the number of thiols to be zero after a finite time. This is analogous to the necessity to disrupt the structure of a protein before using Ellman's procedure. We have used atomic scale molecular dynamics to simulate both cysteine and glutathione in milliQ water. The results showed that, instead of being randomly distributed, cysteine does indeed form aggregates as the Smoluchowski equations indicated. We shall present results for glutathione to (i) establish whether this molecule, which is charged at pH = 6.5, forms aggregates, (ii) if aggregates are formed, whether DTNB will be unable to access thiols hidden inside them.
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Colman, R. W., A. Gewirtz, D. L. Wang, M. M. Huh, B. P. Schick, P. K. Schick, and C. L. Shapiro. "BIOSYNTHESIS AND EXPRESSION OF FACTOR V IN MAGAKARYOCYTES." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642955.

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Coagulation factor V (FV), is a single chain, multifunctional glycoprotein of Mr 350,000 which interacts with a variety of hemostatic proteins such as factor Xa, prothrombin, thrombin and protein C, on the surface of platelets and vascular endothelial cells. FV serves as both a cofactor and substrate in the generation of thrombin and plays a critical regulatory role in both physiologic hemostasis and pathologic thrombosis. The biosynthesis of FV and its subsequent expression are therefore expected to be precisely controlled and may differ in the three sites of synthesis - hepatocytes, endothelial cells, and megakaryocytes (MK). We have previously demonstrated that each guinea pig MK contains 500 times as much FV as in a platelet, as quantified by a competitive enzyme-linked-immunosorbent assay and expresses FV by cytoimmunofluorescence. De novo biosynthesis was demonstrated by incorporation of S-methionine into FV purified on a immunoaffinity column. The purified MK protein exhibited both FV coagulant activity and antigenicity. However, MK FV was more slowly activated by thrombin, more stable in the absence of Ca and exhibited a slightly higher M of 380,000 compared to plasma FV. Similar studies have documented biosynthesis in human MK. In addition, all morphologically recognizable MK enriched by elutriation from human bone marrow contained FV as documented by both monospecific polyclonal and monoclonal antibodies (MAb) to FV. All these cells bound FV since a murine MAb reacting with the light chain of FV (B38) labeled all cells. In contrast, 68% of cells synthesized FV since B10, a MAb to the activation peptide recognizing FV but not FVa, labeled this fraction. To determine whether immature nonnorphologically recognizable MK expressed FV, we identified these cells with an antiserum to human platelet glycoproteins and then probed them with B38. Seventy percent (70%) of such small cells expressed FV. In contrast, no small cells in MK colonies cloned in FV deficient medium expressed FV while only 40% of such colonies contained cells which expressed FV.To further probe the regulation of FV in MK we attempted to correlate the synthesis of FV as probed by MAb B10 with geometric mean cell diameter, stage and ploidy. No significant correlation of FV with any of these indicators of MK maturation. In contrast, preliminary studies suggest that low doses of tetradecanoyl phorbol acetate augment both the number of MK containing FV and the level of FV expressed by individual cells. Thus, FV synthesis may be regulated independent of size, stage, or ploidy and protein kinase C may play a role.To further define the molecular nature of FV in MK we found that purified FV was converted from a monomer to high Mr multimers by an enzyme derived from MK. These multimers resulting from covalent crosslinking since they were stable to SDS, 100° C and reducing agents. The responsible enzyme appeared to be MK FXIIIa since it required C, was inhibited by agents which react with the active site thiol group and was blocked by pseudoamine donor substrates such as putrescine. In addition, FXIIIa was directly demonstrated in guinea pig MK by a specific activity stain. Other investigators have established that FV became irreversibly associated with platelet cytoskeletons after exposure to thrombin. tested whether FXIIIa might mediate this association by performing ligand blotting of platelet membrane proteins using 125I-FV(FV*). Only actin of all the membrane proteins was detected by radioautography. The binding of FV* to the cytoskeleton was dependent in the presence of Ca and FXIIIa. In purified systems crosslinked complexes containing FV* or radiolabeled actin were detected in separate experiments. In whole platelets, the formation of the heteropolymer, after thrombin stimulation, was inhibited by antibodies to FXIII a chain, FV activation peptide (B10) or actin. Endogenous platelet FV was also dependent on FXIII for incorporation into the platelet cytoskeleton after thrombin stimulation. When thrombin-treated FV was crosslinked to actin only the activation peptide (150 kDa) was crosslinked. The light chain or heavy chain of FVa were not involved. Thus FXIIIa play an important role in the binding of FV in platelets to the cytoskeleton during activation and secretion.Further studies of FV in megakaryocytes are necessary to define the regulation of biosynthesis and the control of expression which dictate its critical role in hemostasis and thrombosis.
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8

Dovichi, Norman J., Shade Wu, and Da Yung Chen. "High Sensitivity Fluorescence Detection of Biological Molecules." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/laca.1990.tha1.

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Fluorescein is a good fluorescent label for high sensitivity analysis. The molecule has high molar absorptivity, 5 × 104 L mol-1 cm-1 at 488 nm and near unit fluorescence quantum yield in the pH range of 8 to 10. Unfortunately, the molecule is not photostable undergoing irreversible photobleaching after absorbance of about 8,000 photons. Fluorescein may be used to label amino groups in amino acids, peptides, and proteins through the isothiocyanate derivative. Under basic conditions, the thiocarbamoyl derivative is formed, with relatively good stability. The reaction between amino acids and fluorescein isothiocyanate is first order in bod the concentration of amino acid and derivative, with an activation energy of about 16 kcal/mol. Under acidic conditions, the cyclic thiohydantoin derivative is formed, cleaving the terminal amino acid from proteins and peptides. This thiohydantoin derivative possesses greater photostability than the thiocarbamoyl derivative, decomposing after absorbance of about 12,000 photons. The thiocarbamoyl-thiohydantoin derivative series is the basis of an Edmon degradation scheme for protein sequencing. In addition to amino acid labeling, fluorescein may be used to label thiols through the bromobimane derivatives; a high sensitivity DNA analysis is based on this compound. Last, succinylfluorescein labeled chain terminating dideoxynucleotides are used in DNA sequencing, these molecules have similar spectral properties as fluorescein.
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9

Arnold, Andreas, Christof Stieger, Marco Caversaccio, Martin Kompis, and Jérémie Guignard. "Bone conduction responses of middle ear structures in Thiel embalmed heads." In MECHANICS OF HEARING: PROTEIN TO PERCEPTION: Proceedings of the 12th International Workshop on the Mechanics of Hearing. AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4939368.

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10

Xiao, Lin, Si-Si Liang, Qing Chang, Cong Fu, and Xu Yang. "Exposure of Hela Cells to Serum Results in Increased Cellular Thiol Concentration and Formaldehyde-Induced DNA-Protein Crosslink." In 2009 3rd International Conference on Bioinformatics and Biomedical Engineering (iCBBE 2009). IEEE, 2009. http://dx.doi.org/10.1109/icbbe.2009.5162829.

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Reports on the topic "Proteins thiol"

1

Braun, Alexander. The Interaction between a Thiol Specific Probe (OPA) and the Single Channel Characteristics of the Reconstituted Ca++ Release Protein from Skeletal Muscle Sarcoplasmic Reticulum. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.6745.

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2

Binding of electrophilic chemicals to SH(thiol)-group of proteins and /or to seleno-proteins involved in protection against oxidative stress during brain development leading to impairment of learning and memory. Organisation for Economic Co-Operation and Development (OECD), December 2022. http://dx.doi.org/10.1787/4df0e9e4-en.

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