Mammalian thioredoxin reductases contain a TGA-encoded C-terminal penultimate selenocysteine (Sec) residue, and show little homology to bacterial, yeast, and plant thioredoxin reductases. Here we show that the nematode, Caenorhabditis elegans, contains two homologs related to the mammalian thioredoxin reductase family. The gene for one of these homologs contains a cysteine codon in place of TGA...

The thioredoxin and glutathione systems play a central role in thiol-disulfide redox homeostasis in many organisms by providing electrons to essential enzymes, and defence against oxidative stress. These systems have recently been characterized in platyhelminth parasites, and the emerging biochemical scenario is the existence of linked processes with the enzyme thioredoxin glutathione reductase...

Recycling of ascorbic acid from its oxidized forms is required to maintain intracellular stores of the vitamin in most cells. Since the ubiquitous selenoenzyme thioredoxin reductase can recycle dehydroascorbic acid to ascorbate, we investigated the possibility that the enzyme can also reduce the one-electron-oxidized ascorbyl free radical to ascorbate. Purified rat liver thioredoxin reductase c...

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...

Thioredoxin reductase (EC l&4.5), which catalyzes the reduction of the disulfide bridge in thioredoxin by NADPH, was purified from calf liver and thymus. Preparation methods, involving chromatography on DEAE-cellulose, TEAEcellulose, and Sephadex G-200 or G-100 were used to purify the calf liver enzyme llOO-fold and the thymus enzyme 2800fold. The enzyme was shown to catalyze an NADPH-dependent...

Partial purification of a thioredoxin system from Novikoff ascites hepatoma cells has been previously reported (MOORE, E. C. (1967) Biochem. Biophys. Res. Commun. 29, 264-268). Thioredoxin from the same mammalian source has now been purified to electrophoretic homogeneity by ammonium sulfate fractionation, heat treatment, DEAE-cellulose chromatography, and Sephadex chromatography. 1-Dimethylami...

Thioredoxins (Trxs) are small ubiquitous oxidoreductase proteins with two redox-active Cys residues in a conserved active site (WCG/PPC) that regulate numerous target proteins via thiol/disulfide exchanges in the cells of prokaryotes and eukaryotes. The isoforms OsTrx23 with a typical active site (WCGPC) and OsTrx20 with an atypical active site (WCTPC) are two  Trx h- type isoforms in rice that ...

The so-called thioredoxin system, thioredoxin (Trx), thioredoxin reductase (Trr), and NADPH, acts as a disulfide reductase system and can protect cells against oxidative stress. In Saccharomyces cerevisiae, two thioredoxins (Trx1 and Trx2) and one thioredoxin reductase (Trr1) have been characterized, all of them located in the cytoplasm. We have identified and characterized a novel thioredoxin ...

IscA is a key member of the iron-sulfur cluster assembly machinery found in bacteria and eukaryotes. Previously, IscA was characterized as an alternative iron-sulfur cluster assembly scaffold, as purified IscA can host transient iron-sulfur clusters. However, recent studies indicated that IscA is an iron-binding protein that can provide iron for the iron-sulfur cluster assembly in a proposed sc...

An albumin fraction extracted from wheat flour contains thioredoxin reductase (Mr = 65,000) and a heat-stable thioredoxin (Mr = 15,000) which are separated on DEAE cellulose and further purified by gel filtration. W heat thioredoxin stimulates E. coli ribonucleotide reductase but not chloroplast fructose-bis-phosphatase. The enzyme is NADPH-dependent (Km = 3.2 X 10 -6 m) . In presence of the th...