The discovery of selenoproteins in 1973 was the starting point for today's flourishing selenium field [1,2]. It provided evidence that selenium had biochemical functions that could account for its nutritional effects [3,4]. Further, it opened the selenium field to investigation by the methods of biochemistry, which led to the identification of several more selenoproteins and showed that selenocysteine was the form of the element in animal selenoproteins and in most bacterial ones. Although noteworthy efforts were made to uncover the mechanism of selenocysteine and selenoprotein synthesis using biochemical methods, the problem yielded only when attacked with the methods of molecular biology [5,6]. The bacterial mechanism was characterized first; characterization of the animal mechanism is a work in progress. It is interesting to note that the only genes that are devoted to selenium metabolism are those that support selenoprotein synthesis and selenocysteine catabolism. Consequently, it seems likely that competition for selenium between selenoprotein synthesis and the production of selenium excretory metabolites [7] controls who- body selenium homeostasis. The physiological functions of selenium derive fi-om the catalytic and physical properties of selenoproteins. Selenoproteins such as the glutathione peroxidases and the thioredoxin reductases have redox activities that allow them to serve in oxidant defense. The deiodinases use their redox activities to activate and inactivate thyroid hormones. From these two examples, it can be seen that selenoprotein functions are diverse while having in common a redox mechanism.

Features the many new discoveries have occurred since the 1st edition on Selenium was published in 2001

New investigators who have made important contributions to the field have been added as chapter authors

Inhalt
Contributors.- Foreword.- Preface.- Acknowledgements.- Selenium: A historical perspective.- Part I Biosynthesis of selenocysteine and its incorporation into protein: Selenium metabolism in prokaryotes.- Mammalian and other eukaryotic selenocysteine tRNAs.- Evolution of selenocysteine decoding and the key role of seleno-phosphate synthetase in the pathway of selenium utilization.- SECIS RNAs and K-turn binding proteins. A survey of evolutionary conserved RNA and protein motifs.- SECIS binding proteins and eukaryotic selenoprotein synthesis.- The importance of subcellular localization of SBP2 and EFsec for selenoprotein synthesis.- Selenocysteine biosynthesis and incorporation may require supramolecular complexes.- Part II Selenium-containing proteins: Deletion of selenoprotein P gene in the mouse.- Selenium and methionine sulfoxide reduction.- Selenoprotein W in development and oxidative stress.- The 15-kDa selenoprotein (Sep15): functional analysis and role in cancer.- Regulation of glutathione peroxidase-1 expression.- Selenoproteins of the glutathione system.- New roles of glutathione peroxidase-1 in oxidative stress and diabetes.- Selenoproteins of the thioredoxin system.- Mitochrondrial and cytosolic thioredoxin reductase knockout mice.- Selenium, deiodinases and endocrine function.- Biotechnology of selenium.- Part III Selenium and human health: Selenium, selenoproteins and brain function.- Selenium as a cancer preventive agent.- Peering down the kaleidoscope of thiol proteomics and unfolded protein response in studying the anticancer action of selenium.- Genetic variation among selenoprotein genes and cancer.- Selenium and viral infections.- Role of selenium in HIV/AIDS.- Effects of selenium on immunity and aging.- Selenium and male reproduction.- Mouse models for assessing the role of selenium in health and development.- Drosophila as a tool for studying selenium metabolism and role of selenoproteins.- Selenium in parasites.- Incorporating 'omics'approaches to elucidate the role of selenium and selenoproteins in cancer prevention.- Selenium-induced apoptosis.- Selenoprotein mimics.- Update of human dietary standards for selenium.- Index.