ABSTRACT
Selenium, with atomic number 34, has been enigmatic since its discovery in 1817 by the Swedish chemist Jons Jakob Berzelius. Its chemistry has proved to be novel and has stimulated chemical research leading to modern developments such as the telephone, transistor, and photocopying machine. In biology, it was initially known to be toxic and later shown to be essential, and first identified as a carcinogen and later shown to be anticarcinogenic. The biochemistry of selenium was elusive, as a biochemical function evaded intense research until in 1972, when selenium was identified as a component of the enzyme glutathione peroxidase (1). Research to unravel the full biochemistry of selenium, however, continues to identify new aspects involving the molecular biology of selenium incorporation into proteins and selenium’s role as a regulator of gene expression. This chapter provides a background on selenium history, chemistry, and analysis and then discusses the salient features of the nutritional biochemistry and molecular biology of selenium. The reader is encouraged to seek additional information in a number of recent reviews (2–6) as well as research papers that are cited in the text.
