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Acidic peptides of the lens. 5. S -Sulphoglutathione

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... Such a reaction would involve two reactants, for example glutathione and SO 2 (or SO 3 H), which have both been identified as having a similar nucleophilic capacity against the quinones formed upon wine oxidation [30]. Clarke in 1932 [31] and Waley in 1958 [32], reported the formation of GSSO 3 H from GSSG under excess of Na 2 S 2 O 5 at pH 7, and indicated that at lower pH the reaction is too slow (Fig. 7). To find out if such a mechanism could also occur in wine, the behaviour of GSSG or GSH in the presence of SO 2 (released by Na 2 S 2 O 5 ) in a model wine solution at pH 3.4 was monitored for 24 h (Fig. 7; Supplementary materials: Figs. ...
... The level of SO 2 concentration chosen for these reactions was much lower than both the free and total SO 2 concentration of the white wines used in this study (Table 1). In agreement with Clarke and Waley [31,32], it was found that at the highest concentration of Na 2 S 2 O 5 tested (19.5 mg/L), approximately 30% of GSSG was consumed after 24 h, producing GSH (2.8 mg/L) and GSSO 3 where Na 2 S 2 O 5 was added at lower concentrations, the results were either similar, but with less product being formed, or were not detectable ( Fig. 7; Supplementary materials: Figs. S2 andS3). ...
Article
The impact of minute amounts of oxygen in the headspace on the post-bottling development of wine is generally considered to be very important, since oxygen can either damage or improve the quality of wine. This project aimed to gain new experimental evidence about the chemistry of the interaction between wine and oxygen. The experimental design included 216 bottles of 12 different white wines produced from 6 different cultivars (Inzolia, Muller Thurgau, Chardonnay, Grillo, Traminer and Pinot gris). Half of them were bottled using the standard industrial process with inert headspace and the other half without inert gas and with extra headspace. After 60 days of storage at room temperature, the wines were analysed using an untargeted LC-MS method. The use of a detailed holistic analysis workflow, with several levels of quality control and marker selection, gave 35 metabolites putatively induced by the different amounts of oxygen. These metabolite markers included ascorbic acid, tartaric acid and various sulfonated compounds observed in wine for the first time (e.g. S-sulfonated cysteine, glutathione and pantetheine; and sulfonated indole-3-lactic acid hexoside and tryptophol). The consumption of SO2 mediated by these sulfonation reactions was promoted by the presence of higher levels of oxygen on bottling.
... In the course of that isolation it was noted that other 35S compounds of low molecular weight were formed by mammalian intestine and one of these has now been identified as S[35S]-sulphoglutathione. Waley (1959) has previously reported the isolation of S-sulphoglutathione from mammalian lens. ...
... S-Sulphoglutathione. S-Sulphoglutathione was prepared by a modification of the method described by Waley (1959). Oxidized glutathione (350 mg.; Sigma Chemical Co., St Louis 18, Mo., U.S.A.) was shaken at 370 with 10 ml. of 1-OM-sodium sulphite-O-OlM-cupric sulphate adjusted to pH 7-0 with nitric acid. ...
... These spontaneous thiol-disulfide exchange products were already described in the literature. GS-Cys is a known product of oxidation of GSH and cysteine in PBS (Yoshiba-Suzuki et al., 2011), whereas GS-SO 3 was found in vivo in several studies (Robinson and Pasternak, 1964;Togawa et al., 1988;Waley, 1959). Increasing amounts of mixed disulfides were detected over time, suggesting that these compounds may serve as storage for cysteine equivalents intracellularly (Togawa et al., 1988). ...
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Industrial fed-batch cultivation of mammalian cells is used for the production of therapeutic proteins such as monoclonal antibodies. Besides medium ensuring initial growth, feeding is necessary to improve growth, viability and antibody production. Established processes include a slight acidic main feed and a separate alkaline feed containing L-tyrosine and L-cysteine. Since L-cysteine is not stable at neutral pH, a new derivative, S-sulfocysteine, was tested in neutral pH feeds. In small scale fed-batch processes, the S-sulfocysteine process yielded a comparable maximum viable cell density, prolonged viability and increased titer compared to the two feed system. Bioreactor experiments confirmed the increase in specific productivity. In depth characterization of the monoclonal antibody indicated no change in the glycosylation, or charge variant pattern whereas peptide mapping experiments were not able to detect any integration of the modified amino acid in the sequence of the monoclonal antibody. Finally, the mechanism of action of S-sulfocysteine was investigated, and results pointed out the anti-oxidative potential of the molecule, mediated through an increase in superoxide dismutase enzyme levels and in the total intracellular glutathione pool. Finally, we propose that the increase in specific productivity obtained in the S-sulfocysteine process results from the anti-oxidative properties of the molecule.
... Studies on sulphite production by cells have focused mainly on sulphate-reducing systems in micro-organisms (Schwenn et al., 1988;Kletzin, 1989). Sulphate reduction has been reported in mammalian tissues (Waley, 1959;Wortman, 1963;Robinson & Pasternak, 1964); however, little is known about the mechanism. It is likely that it involves a 3'-phosphoadenylylsulphate sulphotransferase and at least one carrier protein, speculated to be thioredoxin (Schwenn et al., 1988). ...
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The incorporation of [35S]sulphate into macromolecules by rabbit peritoneal polymorphonuclear neutrophils (PMN) in vitro revealed that two major groups of 35S-labelled macromolecules were synthesized by these cells. The first group did not bind to anion-exchange columns at pH 6.0 and contained 60-80% of the total incorporated radiolabel. The second group did bind to anion-exchange columns at pH 6.0 and eluted as a single peak of radioactivity at an ionic strength characteristic of sulphated proteoglycans; it accounted for the remaining incorporated radiolabel. Analysis of this material on Sepharose CL-6B demonstrated that 35S-labelled macromolecules isolated from the cell extract migrated with Kav. of 0.36, while corresponding material isolated from the medium migrated with Kav. of 0.51. When subjected to electrophoresis on SDS/polyacrylamide gels the intact proteoglycan had a molecular mass of approx. 90 kDa and yielded two core proteins of molecular mass 31 kDa and 28 kDa after digestion with chondroitinase ABC. The peak of labelled macromolecules which did not bind to the anion-exchange column was found, by SDS/PAGE, to comprise 35S-labelled proteins of various molecular masses. The 35S label was displaced from this fraction by treatment with 0.1 M-sodium sulphite, suggesting that the radiolabel was in the form of an S-sulpho sulphite derivative. Using the sulphite-trapping agents N-2,4-dinitroanilinomaleimide and cyst(e)ine, [35S]sulphite was detected in the incubation medium of PMN, indicating that these cells were able to synthesize [35S]sulphite from [35S]sulphate. The release of [35S]sulphite from neutrophil cultures was calculated to be 78 pmol/h per 10(6) cells. When exogenous proteins were included in the incubation medium of cell cultures, the [35S]sulphite reacted with these proteins to form a stable 35S-labelled conjugate.
... TPNH also predominates over its oxidized form (TPN) (Glock & McLean, 1955;Bassham, Birt, Hems & Loening, 1959) and it is likely that the rate at which it can be oxidized limits glucose metabolism by the TPN-specific pentose phosphate pathway ( de Duve & Hers, 1957). Glutathione reductase is an abundant enzyme with high activity in most tissues (Rall & Lehninger, 1952) and, like the pentose phosphate pathway enzymes, is present in cells mainly in the extraparticulate fraction (Kinoshita & Masurat, 1957) so that it is likely and in some tissues (e.g. the bovine lens) probable, (Kinoshita & Masurat, 1957) that the reduction of GSSG provides an important route for the oxidation of TPNH (see also Waley, 1959 a). The rate of this reaction would be limited by the availability of GSSG, i.e. by the rate of oxidation of GSH (the 'missing step' of Waley, 1959 b). ...
Article
An enzyme system catalysing the reaction TPNH + GSSO3H ⇋ GSH + SO3H− + TPN+. has been partially purified from pea tissues. The characteristics of the enzyme have been studied.
Article
This chapter discusses naturally occurring peptides. One of the compounds discussed in this chapter contains 2–20amino acid residues and thus has considerably lower molecular weights than even the smaller proteins. The exception is poly-γ -glutamic acid that must be distinguished from proteins on the basis of its composition rather than its size. This chapter discusses peptides from animal cells. Particular peptides are those whose structures are nearly or completely known. Therefore, biosynthesis and function in terms of structure can be considered. On the other hand, general peptides are less well-defined members of the groups of peptides found in, example pituitaries, or insects, or yeast. This chapter also investigates, whether cells contain a peptide pool, and, if so, what its metabolic status is. This chapter illustrates that, apart from the folic acids, glutathione is the only particular peptide that occurs widely. Its “protective” and “regulatory” functions and its role as a coenzyme have been addressed in the chapter.
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The assay recently described (1) for glutathione in an acid medium has been found to include the naturally occurring S-sulfoglutathione. It is pointed out that this method, in combination with ion-exehange chromatography, may actually make up a suitable determination of S-sulfoglutathione.
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1.1. Studies in vitro with human whole blood and with hemolyzates, of the possible synthesis of GSH in blood cells of the circulation are described.2.2. Whole blood and hemolyzates are capable of converting serine into glycine.3.3. Whole blood and hemolyzates incorporate 35S of [35S]cysteine and of [35S]cystine· HCl into GSH.4.4. the presence of a cystine reductase (EC 1.6.4.1) on the blood cell surface is inferred.5.5. Replacement of part of the plasma of whole blood with isotonic glucose solution interferes with glycine incorporation into GSH. This replacement facilitates glycine passage into the blood cells.6.6. Replacement of part of the plasma of whole blood with isotomic phosphate buffer does not significantly elevate glycine passage into the blood cells, the incorporation of glycine into GSH is, however, markedly accelerated.7.7. NaF has no effect on the passage of glycine into the blood cells. However, a8.very marked inhibition of glycine incorporation into GSH of whole blood and of hemolyzates is evident in the presence of added NaF.
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THE urinary amino-acid excretion of the blotched Kenya genet was first shown to be unusual by Datta and Harris1. In a survey of the urinary amino-acid excretion of various animals from the London Zoo, they found that the genet had an exceptionally high excretion of cystine. This was determined by paper chromatographic and polarographic analysis. A large quantity of cysteic acid was formed on oxidation of the urinary amino-acids, and it was reported that the cystine excretion was 1.0-1.5 mg per ml. This was unusual as it represented a greater solubility than that obtained by dissolving known cystine in a solution containing an equivalent concentration of salts and urea2. In cystinuria, a human inherited metabolic disorder, cystine is excreted at this concentration but gives rise to frequent calculus formation, and there was no evidence that the genet ever formed calculi. The other interesting feature was that in human cystinuria there was a failure of tubular reabsorption of lysine, arginine and ornithine as well as cystine, whereas the genet had no disorder of basic amino-acid excretion.
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1. The production of sulfate conjugates is a well-known and established pathway within the field of xenobiotic metabolism. In addition to the usual attachment of a sulfonate grouping via an oxygen atom (O-sulfonates) to yield a sulfate conjugate, so-called ‘N-sulfates’ (N-sulfonates) have been reported and ‘S-sulfates’ (S-sulfonates) mooted to exist. 2. The few examples cited in the literature where the sulfur atom of the sulfonate group was attached directly to a carbon atom of the xenobiotic (C-sulfonates) and subsequently excreted as a metabolite have been collated, examined and reviewed. 3. The potential mechanisms of formation of these C-sulfonates are discussed, both biological and chemical, the potential rôle of the gut microbiome raised and hopefully by highlighting this curiosity further fruitful investigation will be stimulated.
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The NADPH-dependent enzymatic reduction of S-sulfoglutathione (GSSO3H) in liver and peas has been reexamined. Previous reports have indicated that this reaction is catalyzed by a reductase distinct from glutathione reductase. We present evidence, however, that the reduction is due to an initial reaction of GSSO3H with glutathione (GSH), followed by reduction of the glutathione disulfide (GSSG) formed by glutathione reductase and NADPH. This conclusion is based on the finding that the GSSO3H-reducing activity of a homogenate is lost upon either dialysis or gel filtration and is completely regained by adding GSH. The reconstitution was equally efficient in an extensively purified glutathione reductase as in a crude dialyzed tissue supernatant. We have evidence that the reaction between GSSO3H and GSH is catalyzed by a transhydrogenase found in rat liver.
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The discovery in calf lens and characterization of three new tissue constituents is reported. These are S-(α,β-dicarboxyethyl)-cysteine, S-(α,β-dicarboxyethyl)-glutathione and arginyllysylglycine. Ergothioneine has been identified as a constituent of the eye for the first time. A method is described for the analysis of whole extracts of lens on one paper by electrophoresis and chromatography. This could be applied to other tissues.
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A significant problem faced by pharmaceutical companies today is the failure of lead compounds in the later stages of development due to unexpected toxicities. We have used two-dimensional differential in-gel electrophoresis and mass spectrometry to identify a proteomic signature associated with hepatocellular steatosis in rats after dosing with a compound in preclinical development. Liver toxicity was monitored over a 5 day dosing regime using blood biochemical parameter measurements and histopathological analysis. As early as 6 h postdosing, livers showed hepatocellular vacuolation, which increased in extent and severity over the course of the study. Alterations in plasma glucose, alanine aminotransferase, and aspartate aminotransferase were not detected until the third day of dosing and changed in magnitude up to the final day. The proteomic changes were observed at the earliest time point, and many of these could be associated with known toxicological mechanisms involved in liver steatosis. This included up-regulation of pyruvate dehydrogenase, phenylalanine hydroxylase, and 2-oxoisovalerate dehydrogenase, which are involved in acetyl-CoA production, and down-regulation of sulfite oxidase, which could play a role in triglyceride accumulation. In addition, down-regulation of the chaperone-like protein, glucose-regulated protein 78, was consistent with the decreased expression of the secretory proteins serum paraoxonase, serum albumin, and peroxiredoxin IV. The correlation of these protein changes with the clinical and histological data and their occurrence before the onset of the biochemical changes suggest that they could serve as predictive biomarkers of compounds with a propensity to induce liver steatosis.
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Evidence is provided that the sulfite produced by the transamination of cysteinesulfinic acid with α-ketaglutarate or by the oxidative deamination of acid can react with disulfide compounds such as cystine and cystamine, giving origin respectively to S-sulfo-cysteine and S-sulfo-cysteamine.
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A method for simultaneous detection of picomole quantities of glutathione (GSH), glutathione disulfide (GSSG), glutathione S-sulfonate (GSSO3H), and cysteine S-sulfonate (CYSSO3H) by high-performance liquid chromatography has been developed. Compounds are separated by anion-exchange chromatography using a citric acid buffer system, and then derivatized postcolumn using o-phthalaldehyde with 2-mercaptoethanol, heated to 70 degrees C, and detected by fluorescence. The compounds elute with retention times of 12.5 min for GSH, 27.5 min for CYSSO3H, 29.8 min for GSSG, and 33.0 minutes for GSSO3H, with detection limits of 10, 200, 10, and 50 pmol, respectively. Recoveries are 103% for GSH, 102% for GSSG, 100% for CYSSO3H, and 96% for GSSO3H. Determination of target compounds in cells is described.
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A study of the metabolism of cysteine S-sulfate by Penicillium chrysogenum revealed that (a) cysteine-S-sulfate can serve as the sole sulfur source for the organism, (b) a sulfur-regulated permease mediates the transport of cysteine-S-sulfate into the cell and (c) a series of chemical exchange reactions coupled to glutathione reductase (NADPH: glutathione oxidoreductase, EC 1.6.4.2) (to regenerate reduced glutathione) could account for any net cysteine-S-sulfate utilization observable in vivo and in crude extracts. The proposed reactions are: and/or:
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SULPHATE assimilation in Aspergillus nidulans has been shown to involve a step in which thiosulphate reacts with a 3-carbon compound, probably serine, to form S-sulphocysteine as the immediate precursor of cysteine1–5. However, the enzymatic mechanism involved in this assimilatory step has not yet been elucidated. This communication shows that an enzyme preparation obtained from A. nidulans catalyses the condensation of thiosulphate with serine to form S-sulphocysteine if adenosine triphosphate (ATP) and pyridoxal phosphate are added as cofactors.
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Cellfree extracts from Chlorella, spinach leaves or spinach chloroplasts convert radioactive sulfate into a S-sulfocompound already in the dark. The reaction requires ATP, Mg2⊕ ions and compounds with SH groups. The later are needed for activation of the enzym and as substrates and acceptors for the sulfogroup. The compound formed if glutathion is used has been identified as S-sulfoglutathion. Other products formed from sulfate and ATP in the dark by spinach or chlorella extracts are APS and PAPS. The formation of PAPS requires the presence of a SH-group. Both cellfree extracts transfer the sulfate group from APS and PAPS onto glutathion to form S-sulfoglutathion. No ATP is needed in this reaction, neither with PAPS nor with APS as substrate.
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In an assay system containing essentially extract from spinach chloroplasts, 3.3 mM glutathione, O-acetyl-L-serine, and reduced ferredoxin, 35S-cysteine was formed from 35S-adenosine 5′-phosphosulf ate (35S-APS) at a rate of 1 to 6 nmol per mg protein per hour. Addition of non-radioactive adenosine 3′-phosphate 5′-phosphosulf ate (PAPS) to the reaction mixture did not reduce appreciably the rate of 35S-cysteine formation from 35S-APS, indicating that APS is not phosphorylated to PAPS prior to reduction. When glutathione was replaced by dithiothreitol 35S-cysteine was formed at comparable rates. The addition of different spinach thioredoxins did not influence 35S-cysteine formation. Free 35S-SO32− was detected in the reaction mixture with either glutathione or dithiothreitol as active thiol.
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Summary The intoxication of 15-day-old green pea seedlings with 1% gaseous SO2 causes an important concentration fall of some free ketoacids (pyruvic, oxalacetic, α-ketoglutaric) and of glyceraldehyde in the roots and shoots. This fall is a consequence of the reaction of these carbonyl compounds with SO2 in the plant tissue under the formation of bisulphite adducts (α-hydroxysulfonic acids), which have been chemically proved and quantitatively estimated.
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All living organisms require sulfur for various metabolic processes. Sulfur occurs in enzymes, in structural proteins of cells, and in a wide variety of naturally occurring compounds which often play key roles in metabolism. The chemistry and biochemistry of sulfur compounds has been reviewed..
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The authors describe a combination of electrophoretic and classical chromatographic methods, which can be used for investigating free amino-acids or amino-acid compounds in complex biological material, as well as for separating oligopeptides. The essential steps in this procedure are the following: preliminary fractionation by electrophoresis in a volatile buffer of pH 3.9; a two-dimensional combination of electrophoresis at pH 3.9 and chromatography in the solvent butanol-acetic acid-water (acid and weakly basic compounds); a two-dimensional combination of electrophoresis at pH 2.4 and chromatography in the solvent butanol-acetic acid-water, after automatic elution of the neutral compounds separated by the preliminary fractionation at pH 3.9; electrophoresis at pH II.7 and at pH 6.5 after automatic elution of the basic compounds separated by the preliminary fractionation at pH 3.9.The method is convenient and comparatively easy to carry out; only simple and inexpensive apparatus is required.
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This paper constitutes the first description of a previously unreported disorder of metabolism of sulfur-containing compounds. The patient was born with neurological abnormalities and deteriorated to a virtually decorticate state by nine months. Bilateral ectopia lentis was discovered at 1 year. We studied him at age 30 months and found his urine to contain abnormally increased amounts of S-sulfo-l-cysteine, sulfite, and thiosulfate. His urinary excretion of inorganic sulfate was markedly reduced and, in contrast to normal controls, it did not increase after administration of l-cysteine. These chemical abnormalities are best explained by the presence of a block in the conversion of sulfite to sulfate secondary to a deficiency of sulfite oxidase activity. Studies from tissues obtained from the patient postmortem reveal such a defect (5).The pathology could have been caused by toxic effects of accumulation of sulfite or perhaps other metabolites. Possibly, deficiency of inorganic sulfate could also have caused pathological changes. Although three of the patient's seven siblings died in infancy with neurological disease, the remaining siblings and the parents do not bear clinical stigmata suggestive of the patient's disease, and as yet we have detected no chemical abnormalities to suggest they are carriers of a trait. Thus, we suspect, but have no definite evidence, that the disease is an hereditary disorder of metabolism. We have named it sulfite oxidase deficiency.
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Adenosine 5′-phosphosulfate (APS) sulfotransferase and APS reductase have been described as key enzymes of assimilatory sulfate reduction of plants catalyzing the reduction of APS to bound and free sulfite, respectively. APS sulfotransferase was purified to homogeneity from Lemna minor and compared with APS reductase previously obtained by functional complementation of a mutant strain of Escherichia coli with an Arabidopsis thaliana cDNA library. APS sulfotransferase was a homodimer with a monomer M r of 43,000. Its amino acid sequence was 73% identical with APS reductase. APS sulfotransferase purified from Lemna as well as the recombinant enzyme were yellow proteins, indicating the presence of a cofactor. Like recombinant APS reductase, recombinant APS sulfotransferase used APS (K m = 6.5 μm) and not adenosine 3′-phosphate 5′-phosphosulfate as sulfonyl donor. TheV max of recombinant Lemna APS sulfotransferase (40 μmol min−1 mg protein−1) was about 10 times higher than the previously published V max of APS reductase. The product of APS sulfotransferase from APS and GSH was almost exclusively SO3 2−. Bound sulfite in the form ofS-sulfoglutathione was only appreciably formed when oxidized glutathione was added to the incubation mixture. Because SO3 2− was the first reaction product of APS sulfotransferase, this enzyme should be renamed APS reductase.
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Glutathione S-sulfonate (GSSO3H) is a reaction product of glutathione disulfide (GSSG) and sulfite, the hydrated form of sulfur dioxide. In the present study, GSSO3H was found to be a potent competitive inhibitor of the glutathione S-transferases (GST) in the rat liver (Ki = 14 microM) and lung (Ki = 9 microM), and in human lung tumor-derived A549 cells (Ki = 4 microM). GSSO3H was also reduced by a cytosolic enzyme in the rat liver (Km = 313 microM) and lung (Km = 200 microM), and human lung A549 cells (Km = 400 microM). These results suggest that SO2 may affect the detoxification of xenobiotic compounds by inhibiting, via formation of GSSO3H, the enzymatic conjugation of glutathione (GSH) and reactive electrophiles. Although GSSO3H can be enzymatically degraded, the high substrate Km value suggests that this compound may not be readily reduced at low concentrations.
Article
An enzyme has been purified from the green alga Chlorella which transfers sulfate from APS onto glutathion and dithiotreitol. The enzyme does not utilize PAPS unless a crude fraction containing a 3-phosphonucleotidse is used. From the data it is assumed that in photosynthetic sulfte reduction of plants APS rather than PAPS transfers its sulfte group onto a carrier-bound SH-group???replaceable in vitro by glutathion???to form an S-sulfocompound which then might be reduced to the level of sulfide.
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Seventy-one compounds have been tested for their ability to couple with l-glutamic acid to form a γ-glutamyl peptide bond through the action of a purified preparation of γ-glutamyl-cysteine synthetase from bovine lens. The most active amino acids in the system were l-cysteine, l-α-aminobutyrate, and their esters, β-chloro-l-alanine, S-methyl-l-cysteine, l-cycloserine, l-norvaline, allothreonine, allylglycine, β-aminoisobutyrate, and l-homocysteine. The specificity pattern displayed by the enzyme allowed certain conclusions to be drawn concerning its requirements for the cysteine moiety. Several of the isolated enzymic products were hydrolyzed, and formed glutamic acid and the original cysteine analogue. The values for the apparent Km and maximal velocity were determined for many of the reactions.
Article
Inorganic sulfite may be detoxified by conversion to S-sulfocysteine. We demonstrate this conversion by a series of enzyme-catalyzed steps as follows. Inorganic sulfite reacts with glutathione disulfide by a thiol transferase catalyzed reaction as previously demonstrated. The S-sulfoglutathione formed is then converted by γ-glutamyltranspeptidase to S-sulfocysteinylglycine and the latter finally hydrolyzed to S-sulfocysteine by a renal dipeptidase. S-Sulfoglutathione is a substrate for γ-glutamyltranspeptidase as effective as glutathione itself. Furthermore, S-sulfocysteinylglycine is cleaved as efficiently as cysteinylglycine by a renal dipeptidase at high substrate concentrations but somewhat less efficiently at low substrate concentrations.
In tissue culture, protection against X-irradiation by a number of cysteamine derivatives was studied and the results were compared with data obtained in mice. Compounds with a covered SH group, like WR 638, cysteamine phosphate, WR 2721, and AE 48527, showed practically no protection when dissolved in tissue-culture medium, but developed a protective activity when dissolved in rat blood. Thiol measurements demonstrated that in rat blood the compounds were partly hydrolysed to thiols. C511 was also hydrolysed in culture medium and was slightly less effective than cysteamine in culture medium. Cysteamine phosphate was hydrolsed more easily than cysteamine sulphate and the protective activity in rat blood was better. WR 2721 was also partly hydrolysed in rat blood. The in vitro protection of this compound was disappointing when compared with results in vivo. Its SH form (WR 1065) also showed less protection than expected from in vivo experiments. Thus, the little protection by WR 2721 in vitro in rat blood is not only due to its incomplete conversion into its thiol. Longer incubation times and the use of rat blood as a solvent brought the protective activity of WR 1065 almost up to the level of cysteamine. This may indicate that WR 1065 penetrates the cells poorly. WR 1065 was the only compound we studied whose protective activity in vitro was improved appreciably by dissolving it in rat plasma.
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1. The aminolaevulinate synthetase activator of fresh extracts of semi-anaerobically grown Rhodopseudomonas spheroids was resolved into two fractions by ion-exchange chromatography. One fraction was identified as cystine trisulphide (CySSSCy). Analysis of the other fraction indicated the presence of about equal amounts of glutathione trisulphide (GSSSG) and the mixed trisulphide of glutathione and cystine (GSSSCy). 2. Four further fractions with activator activity were observed on ion-exchange chromatography of extracts prepared by methods similar to those described earlier [Neuberger et al. (1973)Biochem. J. 136,491-499]. These activators were generated by the extraction procedure. Two of them have been identified as trisulphanedisulphonate (S5O62-) and additional cystine trisulphide. 3. For the series of polysulphanedisulphonates (-O3S-Sn-SO3-, n greater than or equal to 1), activator activity at muM concentrations was exhibited only by compounds with n greater than 3. This, together with the results described above, indicates that for a compound R-Sn-R' (where R and R' are organic or inorganic groups) the only structural requirement for activity is n greater than or equal to 3. 4. Oxygenation of a semipanaerobic culture of R. spheroids for 1.5h before harvesting the cells produced a decrease of more than 90% in the cellular content of cystine trisulphide and glutathione trisulphides. 5. Chromatography on DEAE-Sephadex confirmed the presence of multiple forms of aminolaevulinate synthetase in extracts of R. spheroides [Tuboi et al. (1970) Arch.Biochem. Biophys. 138,147-154]. Oxygenation of a semi-anaerobic culture resulted in the disappearance of high-activity enzyme (a-form) and the accumulation of low-activity enzyme (b-form) in the cell. Spontaneous activation [Marriott et al. (1969) Biochem. J. 111,385-394] And activation by cystine trisulphide both resulted in the almost complete conversion of the b-form into the a-form.
Article
A mechanistic study was performed to elucidate the biochemical events connected with the cocarcinogenic effect of sulfur dioxide (SO2). Glutathione S-sulfonate (GSSO3H), a competitive inhibitor of the glutathione S-transferases, forms in lung cells exposed in culture to sulfite, the hydrated form of SO2. Changes in glutathione status (total GSH) were also observed during a 1-h exposure. Some cells were pretreated with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) to inhibit glutathione reductase. In human lung cells GSSO3H formed in a concentration-dependent manner, while glutathione (GSH) increased and glutathione disulfide (GSSG) decreased as the extracellular sulfite concentration was increased from 0 to 20 mM. The ratio of GSH/GSSG increased greater than 5-fold and the GSH/GSSO3H ratio decreased to 10 with increasing sulfite concentration. GSSO3H formed in rat lung cells exposed to sulfite, with no detectable effect on GSH and GSSG. GSSO3H also formed from cellular GSH mixed disulfides. GSSO3H formed rapidly, reaching its maximum value in 15 min. The viability of both cell types was unaffected except at 20 mM sulfite. GSSO3H incubated with human lung cells did not affect cellular viability. BCNU inhibited cellular GSSO3H reductase to the same extent as GSSG reductase. These results indicate that GSSO3H is formed in cells exposed to sulfite, and could be the active metabolite of sulfite responsible for the cocarcinogenic effect of SO2 by inhibiting conjugation of electrophiles by GSH.
Article
Sulfur dioxide (SO2) is a major urban air pollutant, resulting from combustion of sulfur containing fossil fuels. It readily dissolves in water forming sulfurous acid, which dissociates to form bisulfite and sulfite ions (collectively referred to as sulfite), in a ratio depending on the pH of the solution (Petering and Shih, 1975):$$S{{O}_{2}}+{{H}_{2}}O\rightleftharpoons {{H}^{+}}+HS{{O}_{3}}^{-}\rightleftharpoons 2{{H}^{+}}+S{{O}_{3}}{{^{2}}^{-}}$$ Sulfur dioxide and sulfite are also commonly used as antimicrobial and antioxidant agents in the preservation of foods and beverages (Chichester and Tanner, 1972).
Article
Introduction Many investigators have reported on the presence of glutathione (GSH) in lens.1 Glutathione has been suspected of serving some important functions in the physiology of the lens, since one of the first observable changes in experimental cataract formation is a marked decrease in GSH concentration. The reason for the presence of the unusually high concentrations of GSH has never been adequately explained. It has been definitely established that one of the factors contributing to the presence of this tripeptide is that the lens is capable of its synthesis. The incorporation of radioactive glycine into the glutathione molecule was demonstrated to occur in the lens by Kinsey and Merriam.2 Recently, GSH synthesis from its component amino acids in lens homogenates was observed by Daisley.3However, other factors leading to the accumulation of this tripeptide have not been thoroughly studied. The present paper is an attempt in this
Article
A colorimetric method for the quantitative analysis of pure amino acids is described. It is a modification of one reported by Yemm and Cocking, which employs cyanide and ninhydrin. The present method avoids the necessity for the preparation of solutions of reduced ninhydrin, which is an unstable reagent difficult to prepare and impracticable to store.The method is applicable to amino acid mixtures when allowances are made for slight variability of color yields, and the presence of interfering compounds.
Biochimie du Soufre, p. 83 Paris: Centre National de la Recherche Scientifique
  • E E Cliffe
  • S G Waley
  • P Handler
  • I Fridovich
Cliffe, E. E. & Waley, S. G. (1958). Biochem. J. 69, 649. Handler, P. & Fridovich, I. (1956). Biochimie du Soufre, p. 83. Paris: Centre National de la Recherche Scientifique. Hunter, G. (1957). J. clin. Path. 10, 161. Hurlbert, R. B., Schmitz, H., Brumm, A. F. & Potter, van R. (1954). J. biol. Chem. 209, 23. Kinoshita, J. H. & Masurat, T. (1957)
  • R S Alm
  • R J P Williams
  • A Tiselius
Alm, R. S., Williams, R. J. P. & Tiselius, A. (1952). Acta chem. scand. 6, 826.
Symp. biochem. Soc. no. 17 ('Glutathione' ) (in the Press)
  • S G Waley
Waley, S. G. (1958). Symp. biochem. Soc. no. 17 ('Glutathione' ) (in the Press).
  • H T Clarke
Clarke, H. T. (1932). J. biol. Chem. 97, 235.
  • H Rosen
Rosen, H. (1957). Arch. Biochem. Biophys. 67, 10.
  • J H Kinoshita
  • T Masurat
Kinoshita, J. H. & Masurat, T. (1957). Arch. Ophthal., Chicago, 57, 266.
  • S G Waley
Waley, S. G. (1956). Biochem. J. 64, 715.
  • A Schoberl
  • G Bauer
Schoberl, A. & Bauer, G. (1957). Angew. Chem. 69, 478.
  • R B Hurlbert
  • H Schmitz
  • A F Brumm
  • Potter
  • R Van
Hurlbert, R. B., Schmitz, H., Brumm, A. F. & Potter, van R. (1954). J. biol. Chem. 209, 23.
  • E W Yemm
  • E C Cocking
Yemm, E. W. & Cocking, E. C. (1955). Analyst, 80, 209.