In response to hydrogen peroxide (H(2)O(2)), the transcription factor Pap1 from Schizosaccharomyces pombe regulates transcription of genes required for adaptation to oxidative stress and for tolerance to toxic drugs. H(2)O(2) induces oxidation of Pap1, its nuclear accumulation and expression of more than fifty Pap1-dependent genes. Oxidation and nuclear accumulation of Pap1 can also be accompli...

Hydrogen sulphide (H(2)S) is emerging as a potential messenger molecule involved in modulation of physiological processes in animals and plants. In this report, the role of H(2)S in modulating photosynthesis of Spinacia oleracea seedlings was investigated. The main results are as follows. (i) NaHS, a donor of H(2)S, was found to increase the chlorophyll content in leaves. (ii) Seedlings treated...

Peroxiredoxins are cysteine-dependent peroxidases that react with hydrogen peroxide, larger hydroperoxide substrates, and peroxynitrite. Protocols are provided to measure Prx activity with peroxide by (1) a coupled reaction with NADPH, thioredoxin reductase, and thioredoxin, (2) the direct monitoring of thioredoxin oxidation, (3) competition with horseradish peroxidase, and (4) peroxide consump...

Thioredoxin reductase and thioredoxin constitute the cellular thioredoxin system, which provides reducing equivalents to numerous intracellular target disulfides. Mammalian thioredoxin reductase contains the rare amino acid selenocysteine. Known as the "21st" amino acid, selenocysteine is inserted into proteins by recoding UGA stop codons. Some model eukaryotic organisms lack the ability to ins...

Thermoanaerobacter indiensis BSB-33 has been earlier shown to reduce Fe(III) and Cr(VI) anaerobically at 60°C optimally. Further, the Gram-positive thermophilic bacterium contains Cr(VI) reduction activity in both the membrane and cytoplasm. The soluble fraction prepared from T. indiensis cells grown at 60°C was found to contain the majority of Fe(III) reduction activity of the microorganism an...

Background: Thioredoxins ("TRX") are ubiquitous 12-kDa oxidoreductase enzyme containing a dithiol-disulfide active site facilitating the reduction of other proteins by cysteine thiol-disulfide exchange. When thioredoxin levels are elevated there is increased cell growth and resistance to the normal mechanism of programmed cell death. An increase in thioredoxin levels seen in many human primary ...

Thioredoxin (Trx) is an oxidoreductase with important physiological function. Imbalances in the NADPH/thioredoxin reductase/thioredoxin system are associated with a number of pathologies, particularly cancer, and a number of clinical trials for thioredoxin and thioredoxin reductase inhibitors have been carried out or are underway. Due to the emerging role and importance of oxidoreductases for h...

COMMENTARY Correction for “Mitochondrial metabolism is regulated by thioredoxin,” by Ian Max Møller, which appeared in issue 11, March 17, 2015, of Proc Natl Acad Sci USA (112:3180–3181; first published March 9, 2015; 10.1073/pnas.1502425112). The authors note that on page 3181, left column, second full paragraph, line 14, “thioredoxin reductase using NADPH” should instead appear as “ferredoxin...

S-Nitrosylation is a reversible post-translational modification on cysteinyl thiols that can modulate the function of redox-sensitive proteins. The S-nitrosylation of mitochondrial proteins has been shown to regulate various mitochondrial activities involved in energy-transducing systems and mitochondrion-driven apoptosis. In isolated rat brain mitochondria, we demonstrate that mitochondrial pr...

Chloroplast-free mutant cells C-2A ' of the green algae Scenedesmus obliquus lack thioredoxin / , which functions in the light activation of chloroplast enzymes, but do con­ tain the regular thioredoxins I and II. When dark-grown algae are transferred to light, thioredoxin / activity appears rapidly and increases in parallel with photosynthetic ac­ tivities; however it precedes chlorophyll bios...