Selenium-containing proteins

All selenium-containing proteins and enzymes in animals, microorganisms and plants incorporate selenocysteine non-specifically105 or as part of Se-dependent antioxidant enzymes such as glutathione peroxidase, (EC 1.11.1.9) which has a Se-cysteine residue in its active site.116 120 An active form of Se, selenophosphate, is produced by selenophosphate synthetase in several bacteria. This active form is required for the production of Secys-tRNA, a precursor for Se-cysteine.121 In a similar vein, a Se-containing modified-tRNA nucleoside, 5-methylaminomethyl-2-selenouridine, encodes a selenouridine synthase which replaces sulfur in tRNA with selenium.122... 

Polatajko, A., Encinar, J. R., Schaumloffel, D., and Szpunar, J., Quantification of a selenium-containing protein in yeast extract via an accurate determination of a tryptic peptide by species-specific isotope dilution capillary HPLC-ICP MS, Chemia Analityczna 50(1), 265-278, 2005. 

J. Susanne Becker, for joining me in a new and interesting cooperation on metal-, phosphorus-and selenium-containing proteins (metallo-, phospho- and selenoproteomics) using a combination of LA-ICP-MS and MALDI-MS. 

H. Chassaigne, C. C. Chery, G. Bordin, F. Vanhaecke, A. R. Rodriguez, Two-dimensional gel electrophoresis technique for yeast selenium-containing proteins. 

J. Ruiz Encinar, L. Ouerdane, W. Buchmann, J. Tortajada, R. -obin ski, J. Szpunar, Identibcation of water-soluble selenium-containing proteins in selenized yeast by size-exclusion-re versed-phase HPLC/ICPMS followed by MALDI-TOF and electrospray Q-TOF Mass Spectrometry, Anal. Chem., 75 (2003), 3765D3774. 

H. Chassaigne, C. C. Chery, G. Bordin, F. Vanhaecke, A. R. Rodriguez, 2-Dimensional gel electrophoresis technique for yeast selenium-containing proteins - sample preparation and MS approaches for processing 2-D gel protein spots, J. Anal. Atom. Spec-trom., 19 (2004), 85-95. 

J. T. Deagen, M. A. Beilstein, P. D. Whanger, Chemical forms of selenium in selenium containing proteins from human plasma, J. Inorg. Biochem., 41 (1991), 261-268. 

S. Monicou, J. Meija, J. A. Caruso, Preliminary studies on selenium-containing proteins in Brassica juncea by size exclusion chromatography and fast protein liquid chromatography coupled to ICP-MS, Analyst, 129 (2004), 116D123. 

Asplund K (2002) Antioxidant vitamins in the prevention of cardiovascular disease a systematic review. Journal of Internal Medicine 2, 372-92. BehneDandKyriakopoulosA(2001) Mammalian selenium-containing proteins. Annual Reviews of Nutrition 21,453-73. 

Behne D and Kyriakopoulos A(2001) Mammalian selenium-containing proteins. Annual Reviews of Nutrition 21,453-73. 

The constmction of synthetic selenocysteine-containing proteins or selenium-containing proteins attracts considerable interest at present, mainly for the reason that it can be used to solve the phase problem in X-ray crystallography. Selenomethionine incorporation has been used mostly uutil now for this purpose. There are also two reports ou uew synthetic selenocysteine-containing proteins. In one case, the active site serine of subtUisin has been converted into a selenocysteine residue by chemical means, with the result that the enzyme gains a predominant esterase instead of protease activity. In the second case, automated peptide synthesis was carried out to produce a peptide in which all seven-cysteine residues of the Neurospora crassa metallothioueiu (Cu) were replaced by selenocysteine. The replacement resulted iu au alteration of both the stoichiometry and the affinity of copper binding. ... 

Selenoprotein P. This protein is the major selenium-containing protein in blood plasma, may be a transport protein for the element, and has an antioxidant function. ... 

Although selenium compounds are notorious for being toxic and often have a particularly unpleasant smell, the element selenium has significant biological relevance Selenium is an essential trace element and some selenium-containing proteins, e.g., glutathione peroxidase, have been discovered. 

As a component of glutathione peroxidase and the iodothyronine 5 -deiodinases, selenium is an essential micronutrient for humans. Its role in the deiodinase enzymes may be one reason that children require more selenium for growth than adults. Selenium is also a component of the enzyme thioredoxin reductase, which catalyses the NADPH-dependent reduction of the redox protein thioredoxin. Other selenium-containing proteins of unknown functions, including selenoprotein P found in the plasma, have also been identified. Excess selenium administered as selenite and selenate has been shown to be metabolized to methylated compounds and excreted. 

Little is known about the specific biochemical mechanism(s) by which selenium and selenium compounds exert their acute toxic effects. Long-term effects on the hair, skin, nails, liver, and nervous system are also well documented, and a general theory has been developed to explain the toxicity of exposure to excess selenium, as discussed below. Generally, water-soluble forms are more easily absorbed and are generally of greater acute toxicity. Mechanisms of absorption and distribution for dermal and pulmonary uptake are unknown and subject to speculation, but an active transport mechanism for selenomethionine absorption in the intestine has been described (Spencer and Blau 1962). The mechanisms by which selenium exerts positive effects as a component of glutathione peroxidase, thioredoxin reductase, and the iodothyronine 5 -deiodinases are better understood, but the roles of other selenium-containing proteins in mammalian metabolism have not been clarified. 

Gesteland, RF University of Utah Genetic analysis of synthesis of selenium containing proteins CRISP 2001... 

Very recently, a selenium-containing protein with a molecular weight of approximately... 

The lack of influence of cadmium on GSH-Px activity in our studies is consistent with the results of Prohaska et al. (1977) but is at variance with those of Omaye and Tappel (1975). The reasons for this disagreement are not readily apparent. In work with rat testis cytosol, two different GSH-Px activities were found when assayed with cumene hydroperoxide (Prohaska et al, 1977). The larger MW species eluted with the void volume on Sephadex G-150 columns and incorporated Se from selenite, but the smaller one (42,000 MW) did not incorporate Se from radioactive selenite. When CdCl2 was given to rats injected 4 wk previously with a tracer dose of Se-selenite, Sephadex G-150 chromatography of testis cytosol showed that most of the ° Cd was eluted in a major peak of 34,000 MW, but very little Cd was found in association with a major Se peak (140,000 MW) or with GSH-Px activity. Thus, under homeostatic conditions, cadmium does not appear to bind to the major selenium-containing protein or to GSH-Px in the testes. 

L. Tastet, D. Schaumloffel, B. Bouyssiere and R. Lobinski, Identification of selenium-containing proteins in selenium-rich yeast aqueous extract by 2D gel electrophoresis, nanoHPLC-ICP MS and nanoHPLC-ESI MS/ MS, Talanta, 2008, 75(4), 1140-1145. 

Koyama, H., Omura, K., Ejima.A., Kasanuma,Y.,Watanabe, C., and Satoh, H. (1999). Separation of selenium-containing proteins in human and mouse plasma using tandem high-performance liquid chromatography columns coupled with inductively coupled plasma-mass spectrometry. Anal. Biochem. 267(1), 84. 

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