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Selenium in biology. Selenocysteine is the main organic molecule involving selenium in humans. Selenium is an essential micronutrient for animals, though it is toxic in large doses. In plants, it sometimes occurs in toxic amounts as forage, e.g. locoweed. Selenium is a component of the amino acids selenocysteine and selenomethionine.
Selenium compounds commonly exist in the oxidation states −2, +2, +4, and +6. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. [12]
Selenium compounds. Selenium compounds are compounds containing the element selenium (Se). Among these compounds, selenium has various oxidation states, the most common ones being −2, +4, and +6. Selenium compounds exist in nature in the form of various minerals, such as clausthalite, guanajuatite, tiemannite, crookesite etc., and can also ...
Organoselenium chemistry. Organoselenium chemistry is the science exploring the properties and reactivity of organoselenium compounds, chemical compounds containing carbon -to- selenium chemical bonds. [ 1][ 2][ 3] Selenium belongs with oxygen and sulfur to the group 16 elements or chalcogens, and similarities in chemistry are to be expected.
Nutrient. A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures such as hair, scales, feathers, or exoskeletons.
Choline. Vitamin A (e.g. retinol (see also - provitamin A carotenoids)) Vitamin C (Ascorbic acid) Vitamin D. Ergocalciferol. Cholecalciferol. Vitamin E ( tocopherols and tocotrienols) Vitamin K. Vitamin K 1 (phylloquinone)
Micronutrient. Micronutrients are essential dietary elements required by organisms in varying quantities to regulate physiological functions of cells and organs. [ 1][ 2] Micronutrients support the health of organisms throughout life. [ 3][ 4][ 5] In varying amounts supplied through the diet, micronutrients include such compounds as vitamins ...
Selenium is toxic in high concentrations. As sodium selenite, the chronic toxic dose for human beings was described as about 2.4 to 3 milligrams of selenium per day. [7] In 2000, the US Institute of Medicine set the adult Tolerable upper intake levels (UL) for selenium from all sources - food, drinking water and dietary supplements - at 400 μg/day. [8]