Selenium-containing enzymes in mammals: Chemical perspectives

  title={Selenium-containing enzymes in mammals: Chemical perspectives},
  author={Gouriprasanna Roy and Bani Kanta Sarma and Prasad P. Phadnis and Govindasamy Mugesh},
  journal={Journal of Chemical Sciences},
The chemical and biochemical route to the synthesis of the 21st amino acid in living systems, selenocysteine, is described. The incorporation of this rare amino acid residue into proteins is described with emphasis on the role of monoselenophosphate as selenium source. The role of selenocysteine moiety in natural mammalian enzymes such as glutathione peroxidase (GPx), iodothyronine deiodinase (ID) and thioredoxin reductase (TrxR) is highlighted and the effect of other amino acid residues… 
Application of dehydroalanine as a building block for the synthesis of selenocysteine-containing peptides
Selenocysteine (Sec), the 21st proteinogenic amino acid, is inserted co-translationally into number of natural proteins. It is coded by a dual function stop codon UGA (opal). It is a redox active
Enzyme Mimetic Chemistry of Organoselenium Compounds
In this chapter, some of the well-studied examples of selenoenzymes and their synthetic mimics are discussed and the role of Sec in iodothyronine deiodinases, which control the thyroid hormone levels, is also discussed.
Synthetic Mimics of Selenoproteins
Different catalytic mechanisms proposed in the literature for the GPx-like antioxidant activities of ebselen and related selenenyl amides are described.
Selenazolidine: a selenium containing proline surrogate in peptide science.
A wide range of potential uses of the Sez amino acid in peptide chemistry are suggested, for instance as a viable proline surrogate as well as a selenium probe, complementary to Sec and SeMet, for NMR and mass spectrometry analytical purposes.
Introduction of a catalytic triad increases the glutathione peroxidase-like activity of diaryl diselenides.
This study has synthesized a series of amine or amide-based diselenides containing an additional amino group as glutathione peroxidase (GPx) mimetics that act as a catalytic triad model of the native GPx featuring two basic amino groups near the selenium centre.
Synthesis and antioxidant activity of peptide-based ebselen analogues.
The PN-scavenging activity of the Phe-based peptide analogues was found to be comparable to that of the Val-based compounds, and the difference in the catalytic activity of dipeptide-based ebselen derivatives can be ascribed mainly to the change in the reactivity of these compounds toward GSH and peroxide.
A simple and efficient strategy to enhance the antioxidant activities of amino-substituted glutathione peroxidase mimics.
The glutathione peroxidase (GPx) activities of some diaryl diselenides incorporating tertiary amino groups were studied and revealed that the simple 6-OMe groups play multiple roles in each of the catalytically active intermediates by introducing steric and electronic effects that are required for efficient catalysis.
Stable selones in glutathione-peroxidase-like catalytic cycle of selenonicotinamide derivative.
Estimated reactivity parameters for the reaction of selenium species, according to the Dalziel kinetic model, towards GSH (ϕGSH) and H2O2 ( ϕH2O 2), indicated that the rate constant for the Reaction of NictSeSeNict with GSH is higher as compared to that with H2 O2, indicating that the activity is initiated by reduction.
Selenium biochemistry and its role for human health.
This review summarizes the most recent findings on the biochemistry of active selenium species in humans, and addresses the latest evidence on the link betweenselenium intake, selenoproteins functionality and beneficial health effects.


Selenium Proteins Containing Selenocysteine
Selenocysteine can be considered the 21st amino acid since its incorporation is DNA-encoded and its cotranslational insertion follows a route independent in many features from the path of insertion of the 20 classical amino acids.
Selenocysteine: the 21st amino acid
The aim of this article is to review the events leading to the elucidation of selenocysteine as being the 21st amino acid.
Bacterial selenocysteine synthase--structural and functional properties.
Kinetic analysis of the enzyme showed that thiophosphate served as a substrate leading to cysteyl-tRNA(Sec) synthesis, albeit with a 330-fold lower catalytic efficiency, and data together with the finding that selenoph phosphate synthetase is highly specific for selenide indicate that the phosphate moiety of selenophile provides selenocysteine synthase with the discrimination specificity against sulfur.
Three-dimensional structure of a mammalian thioredoxin reductase: Implications for mechanism and evolution of a selenocysteine-dependent enzyme
The results suggest that mammalian TrxR evolved from the GR scaffold rather than from its prokaryotic counterpart, which renders cell growth dependent on selenium.
Structure and mechanism of mammalian thioredoxin reductase: the active site is a redox-active selenolthiol/selenenylsulfide formed from the conserved cysteine-selenocysteine sequence.
Mammalian thioredoxin reductases (TrxR) are homodimers, homologous to glutathione reductase (GR), with an essential selenocysteine residue in an extension containing the conserved C-terminal sequence -Gly-Cys-Se Cys-Gly, compatible with known enzyme activities and the effects of inhibitors.
Identification of type I iodothyronine 5'-deiodinase as a selenoenzyme.
Various functions of selenols and thiols in anaerobic Gram‐positive, amino acids‐utilizing bacteria
Electron transfer reactions for the reduction of glycine in Eubacterium acidaminophilum involve many selenocysteine (U)‐ and thiol‐containing proteins, as shown by biochemical and molecular analysis.
The crystal structure of seleno-glutathione peroxidase from human plasma at 2.9 A resolution.
Compared to the bovine erythrocyte enzyme, a number of residues in the active site are mutated or deleted in the plasma enzyme, including all the residues that were previously suggested to be involved in glutathione binding.
Monoselenophosphate: synthesis, characterization, and identity with the prokaryotic biological selenium donor, compound SePX.
Addition of chemically prepared monoselenophosphate caused a dose-dependent decrease in the amount of 75Se incorporated into tRNAs from 75SePX generated in situ by SELD enzyme.