Glutathione Is the Resolving Thiol for Thioredoxin Peroxidase Activity of 1-Cys Peroxiredoxin Without Being Consumed During the Catalytic Cycle.

Aims: A three-step catalytic cycle is common to all peroxiredoxins (Prxs), despite structural and kinetic differences. The second step in 1-Cys type Prxs is a matter of debate since they lack an additional cysteine to play the resolving role, as happens with the 2-Cys Prxs. The aim of this study was to elucidate the role of glutathione (GSH) in the thioredoxin-dependent peroxidase activity of Saccharomyces cerevisiae mitochondrial Prx1p, a 1-Cys type Prx.

Immune response of goats immunised with glutathione S-transferase and experimentally challenged with Fasciola hepatica.

Glutathione S-transferase (FhGST) purified from Fasciola hepatica adult worms was used to immunise goats against F. hepatica in an experimental infection; the level of protection, in terms of fluke burden, faecal egg counts and hepatic damage was determined, as well as the humoral and cellular immune response elicited. Animals were allocated into three groups of six animals each: group 1 (immunised with FhGST and infected), group 2 (unimmunised and infected), and group 3 (unimmunised and uninfected).

[Prognostic factors associated with postoperative complications in liver transplant].

Objectives: the postoperative evolution of patients submitted to orthotopic liver transplant (OLT) is frequently associated with the appearance of different types of complications such as renal failure, graft rejection, infections, and neurological disorders. These complications are the most significant causes of early morbidity and mortality in patients undergoing OLT. The purpose of the present study was the identification of factors related to the different postoperative complications after OLT.

Changes in the proteome of functional and regressing corpus luteum during pregnancy and lactation in the rat.

The corpus luteum (CL) is an exquisitely regulated transitory endocrine gland necessary for the onset and maintenance of pregnancy in mammals. Most of the data on the mechanisms of CL differentiation at the molecular level come from genomic studies, but direct protein data are scarce. Here we have undertaken a differential expression proteomic approach to identify, in an unbiased way, those proteins whose levels change significantly in the rat CL as it evolves from functionality during pregnancy to regression after parturition.

Expression of glutaredoxin (thioltransferase) in the rat ovary during the oestrous cycle and postnatal development.

Glutaredoxins (Grxs) are low-molecular-weight proteins which participate in redox events in association with glutathione (GSH) and are involved in a variety of cellular processes. It is known that oxidative stress plays important physiological roles within the ovary. In the present study, we have prepared specific antibodies against rat Grx and have used them to localize the protein in the ovaries of rats during postnatal development and during the oestrous cycle, by immunohistochemical methods.

Glutaredoxins catalyze the reduction of glutathione by dihydrolipoamide with high efficiency.

Glutaredoxins (Grx) are small (approximately 12kDa) proteins which catalyze thiol disulfide oxidoreductions involving glutathione (GSH) and disulfides in proteins or small molecules. Here, we present data which demonstrate the ability of glutaredoxins to catalyze the reduction of oxidized glutathione (GSSG) by dihydrolipoamide (DHL), an important biological redox catalyst and synthetic antioxidant. We have designed a new assay method to quantify the rate of reduction of GSSG and other disulfides by reduced lipoamide and have tested a set of eight recombinant Grx from human, rat, yeast, and E.

Two isoforms of Saccharomyces cerevisiae glutaredoxin 2 are expressed in vivo and localize to different subcellular compartments.

Glutaredoxin (Grx)2 from Saccharomyces cerevisiae is a member of the two-cysteine (dithiol) subfamily of Grxs involved in the defence against oxidative stress in yeast. Recombinant yeast Grx2p, expressed in Escherichia coli, behaves as a 'classical' Grx that efficiently catalyses the reduction of hydroxyethyl disulphide by GSH. Grx2p also catalyses the reduction of GSSG by dihydrolipoamide with even higher efficiency.

Immunolocalization of glutaredoxin in the human corpus luteum.

Glutaredoxin (Grx) is a small protein with oxidoreductase activity which is involved in the cellular defence against oxidative stress. Corpus luteum (CL) regression has been related to the generation of reactive oxygen species (ROS). We have studied the presence of glutaredoxin in the human ovary during the ovulatory cycle using polyclonal antibodies developed against recombinant human Grx.

Characterization of mammalian thioredoxin reductase, thioredoxin and glutaredoxin by immunochemical methods.

Specific polyclonal antibodies towards the oxidized form of bovine thioredoxin reductase (TR) have been obtained in rabbits, and purified. The antigenicity was lost upon reduction of TR by NADPH indicating a large conformational change upon reduction of the redox-active disulfide in the enzyme. The antibodies did not cross-react with other bovine NADPH-dependent dehydrogenases.

Purification from placenta, amino acid sequence, structure comparisons and cDNA cloning of human glutaredoxin.

Glutaredoxin is generally a glutathione-dependent hydrogen donor for ribonucleotide reductase and also catalyses general glutathione (GSH)-disulfide-oxidoreduction reactions in the presence of NADPH and glutathione reductase. A Glutaredoxin from human placenta was purified to homogeneity, as judged by SDS/PAGE and IEF (12 kDa). Purification was monitored by the activity with hydroxyethyl disulfide as a substrate.

Null thioredoxin and glutaredoxin Escherichia coli K-12 mutants have no enhanced sensitivity to mutagens due to a new GSH-dependent hydrogen donor and high increases in ribonucleotide reductase activity.

This work investigates whether a mutator phenotype is associated to the simultaneous deficiency in thioredoxin and glutaredoxin, the two known hydrogen donors of ribonucleotide reductase. To this end, new Escherichia coli K-12 strains carrying delta trxA and/or grx::kan null mutations were constructed to monitor mutagenesis by selecting forward mutations to L-arabinose resistance. Highly sensitive and specific enzyme-linked immunoassays were developed to confirm that trx-grx- cells lacked thioredoxin and glutaredoxin.

Topological relationships between porcine anterior pituitary hormones and the thioredoxin and glutaredoxin systems.

Thioredoxin (TRX) and glutaredoxin (GRX) had previously been localized in folliculo-stellatae (FS) cells and in only a fraction of glandular cells of the anterior pituitary (Padilla et al., 1992). Here we report on a double immunolabelling study carried out to determine the correlation between the type of secretory cell and the presence of TRX or GRX.

Immunochemical characterization and tissue distribution of glutaredoxin (thioltransferase) from calf.

Glutaredoxin catalyzes glutathione-dependent disulfide oxidoreduction reactions in a coupled system with NADPH, GSH and glutathione reductase and has an active site disulfide/dithiol with the sequence -Cys-Pro-Tyr-Cys-. Calf thymus glutaredoxin (thioltransferase), which contains two additional structural half-cystine residues, was purified to homogeneity, using a modification of the previously described isolation procedure. This method involved a pI-shift of glutaredoxin, obtained after oxidation of the fully reduced form with hydroxyethyl-disulfide, followed by CM-Sepharose chromatography.

Regulation of horse-liver glutathione reductase.

1. The enzyme was rapidly inactivated by NAD(P)H, GSH, dithionite or borohydride, while activity increased in the presence of NAD(P)+ or GSSG. NADH was more efficient for inactivation than NADPH.

Horse-liver glutathione reductase: purification and characterization.

1. Purification of horse-liver glutathione reductase was obtained by affinity chromatography on N6-(6-aminohexyl)-adenosine-1'5'-bisphosphate Sepharose (N6-2'5'-ADP-Sepharose) and Reactive Red-120-Agarose, and chromatography on DEAE-Sephadex and Sephacryl S-300. 2.

Purification and properties of bovine thioredoxin system.

Using a variety of chromatographic techniques, a crude extract from bovine liver was fractionated to obtain pure preparations of thioredoxin reductase, thioredoxin, glutaredoxin and glutathione reductase with good yields. The turbidimetric assay of thioredoxin with insulin as the disulfide substrate was optimized; by incorporation of the lag time (tau) into the calculations, linearity was maintained for a wider range of thioredoxin concentrations, and a distinction could be made between reduced and non-reduced forms. Subunit composition and molecular mass, absorption spectrum and kinetic parameters of thioredoxin reductase were similar to those of other mammalian thioredoxin reductases.

Immunolocalization of thioredoxin and glutaredoxin in mammalian hypophysis.

Thioredoxin (TRX) and glutaredoxin (GRX) are two small proteins catalyzing thiol-disulfide oxidoreductions. A role of both proteins in secretory processes has been suggested and recently it has been demonstrated that thioredoxin functions as a growth factor for lymphocytes in cell cultures. Here we report on the immunolocalization by light microscopy of both proteins in the hypophysis of mammals.

NADPH and oxidized thioredoxin mediate redox interconversion of calf-liver and Escherichia coli thioredoxin reductase.

The activity of pure calf-liver and Escherichia coli thioredoxin reductases decreased drastically in the presence of NADPH or NADH, while NADP+, NAD+ and oxidized E. coli thioredoxin activated both enzymes significantly, particularly the bacterial one. The loss of activity under reducing conditions was time-dependent, thus suggesting an inactivation process: in the presence of 0.

Metals are directly involved in the redox interconversion of Saccharomyces cerevisiae glutathione reductase.

Redox inactivation of glutathione reductase involves metal cations, since chelators protected against NADPH-inactivation, 3 microM EDTA or 10 microM DETAPAC yielding full protection. Ag+, Zn2+ and Cd2+ potentiated the redox inactivation promoted by NADPH alone, while Cr3+, Fe2+, Fe3+, Cu+, and Cu2+ protected the enzyme. The Zn2+ and Cd2+ effect was time-dependent, unlike conventional inhibition.