Recent Developments in Selenium Metabolism and Chemical Speciation: A Review

• Published in: Journal of trace elements in medicine and biology Vol. 13; no. 4; pp. 193 - 214
• Main Authors: Patching, S.G., Gardiner, R.H.E.
• Format: Journal Article
• Language: English
• Published: Stuttgart Elsevier GmbH 01.12.1999; Fischer; Elsevier
• Subjects: Animals; Biochemistry, Molecular Biology; Biological and medical sciences; Body Fluids - metabolism; Chemical Sciences; chemical speciation; Codon; Fundamental and applied biological sciences. Psychology; Humans; Inorganic chemistry; Life Sciences; metabolism; Metabolisms and neurohumoral controls; Proteins - metabolism; Selenium; Selenium - metabolism; selenium status; Selenoproteins; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Water and mineral metabolism. Osmoregulation. Acidobasic balance; selenium status; metabolism; Selenium; selenoproteins; chemical speciation; Human; Molecular form; Selenoprotein; Trace element (nutrient); Antioxidant; Metabolism; Biological activity
• ISSN: 0946-672X; 1878-3252
• DOI: 10.1016/S0946-672X(99)80037-6

The biological roles of selenium and its mode of action have only recently begun to be revealed. To date, the major functions of selenium can be attributed to its antioxidative properties and its role in the regulation of thyroid hormone metabolism, cell growth and eicosanoid biosynthesis. The unusual feature of selenoprotein synthesis is that selenocysteine insertion is specified by the stop UGA codon. A number of selenocysteine-specific gene products and a stem-loop structure in the 3′ untranslated region are required for selenocysteine biosynthesis and the decoding of UGA codons in the open reading frame of the mRNA. The major biological functions of selenium are achieved through its redox activity when present as selenocysteine at the active sites of selenoproteins and these proteins are selenium-dependent since replacement with the sulphur analogue cysteine causes loss of enzyme activity. Both organic and inorganic forms of selenium may be utilised by the body, with the selenoamino acids showing greatest bioavailability. Knowledge of the biochemistry of the element coupled with appropriate techniques for the study of the distribution of selenium species in health and disease could help to identify sensitive markers of selenium status.