Selenocysteine, identified as the penultimate C-terminal residue in human T-cell thioredoxin reductase, corresponds to TGA in the human placental gene.

@article{Gladyshev1996SelenocysteineIA,
  title={Selenocysteine, identified as the penultimate C-terminal residue in human T-cell thioredoxin reductase, corresponds to TGA in the human placental gene.},
  author={V. Gladyshev and K. Jeang and T. Stadtman},
  journal={Proceedings of the National Academy of Sciences of the United States of America},
  year={1996},
  volume={93 12},
  pages={
          6146-51
        }
}
The possible relationship of selenium to immunological function which has been suggested for decades was investigated in studies on selenium metabolism in human T cells. One of the major 75Se-labeled selenoproteins detected was purified to homogeneity and shown to be a homodimer of 55-kDa subunits. Each subunit contained about 1 FAD and at least 0.74 Se. This protein proved to be thioredoxin reductase (TR) on the basis of its catalytic activities, cross-reactivity with anti-rat liver TR… Expand
Molecular Cloning and Characterization of a Mitochondrial Selenocysteine-containing Thioredoxin Reductase from Rat Liver*
TLDR
The specific localization of TrxR2 in mitochondria, together with the previous identification of mitochondria-specific thioredoxin and thiOREDoxin-dependent peroxidase, suggest that these three proteins provide a primary line of defense against H2O2 produced by the mitochondrial respiratory chain. Expand
Essential Role of Selenium in the Catalytic Activities of Mammalian Thioredoxin Reductase Revealed by Characterization of Recombinant Enzymes with Selenocysteine Mutations*
TLDR
Mammalian thioredoxin reductases (TrxR) are dimers homologous to glutathione reductase with a selenocysteine residue with the essential role of this trace element in cell growth explained. Expand
Highly active dimeric and low-activity tetrameric forms of selenium-containing rat thioredoxin reductase 1.
TLDR
The characterization of these different forms of recombinant TrxR1 revealed that inherent turnover capacity of the enzyme must be revised, that multimeric states of the protein may be formed, and that the yield of bacterial selenoprotein production may be lower than earlier reported. Expand
Efficiency of selenocysteine incorporation in human thioredoxin reductase.
TLDR
Monoclonal antibodies to human TR are developed, and a sandwich enzyme-linked immunosorbent assay to determine TR protein content is established, and it is observed that the specific activity of cytosolic TR in NCI-H441 cells increased with increasing concentrations of Se in a serum-free medium. Expand
Rat and Calf Thioredoxin Reductase Are Homologous to Glutathione Reductase with a Carboxyl-terminal Elongation Containing a Conserved Catalytically Active Penultimate Selenocysteine Residue*
TLDR
The bovine and rat thioredoxin reduct enzyme sequences revealed a close homology to glutathione reductase including the conserved active site sequence (Cys-Val-Asn- Val-Gly-Cys) and confirmed the identity of a previously published putative human thiOREDoxin reduCTase cDNA clone. Expand
INVESTIGATION INTO THE ROLE OF THE C-TERMINAL VICINAL CYSTEINE RESIDUES IN HIGH Mr THIOREDOXIN REDUCTASES
Mammalian thioredoxin reductase (TR) contains the rare amino acid selenocysteine (Sec), which is essential for the enzyme’s catalytic activity. Substitution of the catalytic Sec residue for aExpand
Overexpression of wild type and SeCys/Cys mutant of human thioredoxin reductase in E. coli: the role of selenocysteine in the catalytic activity.
TLDR
The three gene products were purified using a standard isolation protocol and exhibited characteristic thiolate-flavin charge transfer spectra upon reduction, with DTNB as substrate, compared to native rat liver thioredoxin reductase. Expand
Active sites of thioredoxin reductases: Why selenoproteins?
TLDR
It is shown that the serine residues flanking the C-terminal Cys residues of Drosophila TrxRs are responsible for activating the cysteines to match the catalytic efficiency of a selenocysteine-cysteine pair as in mammalian TrxR, obviating the need for selenium. Expand
The C-Terminal Tetrapeptide Sequence of Drosophila Thioredoxin Reductase Does not Function as a Redox-active Motif in the Human Lung Counterpart
TLDR
The isozymes of mammalian thioredoxin reductase (TrxR) contain the penultimate selenocysteineresidue (SeCys) in the redox-active C-terminal tetrapeptide, which is conserved among other insect TrxRs such as those of honeybee and fruit fly. Expand
Heterogeneity within Animal Thioredoxin Reductases
TLDR
A remarkable heterogeneity within TRs is demonstrated, which, at least in part, results from evolutionary conserved genetic mechanisms employing alternative first exon splicing. Expand
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