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threonine

threonine (thrē´ənēn), organic compound, one of the 22 α-amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. It is one of several essential amino acids needed in the diet; human beings cannot synthesize it from simpler metabolites. Young adults need about 14 mg of this amino acid per day per kilogram (6 mg per lb) of body weight. Although threonine participates in many reactions in bacteria, including the biosynthesis of vitamin B12 and isoleucine, its metabolic role in higher animals, including man, remains obscure. It is known only as a constituent of proteins, and even in that form it is relatively unreactive. In spite of the fact that its side chain has a hydroxyl group similar to that of serine, there is no indication that it participates in the catalytic functions of any enzyme. Threonine was isolated from the protein fibrin in 1935 and synthesized in the same year.

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"threonine." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 23 Aug. 2017 <http://www.encyclopedia.com>.

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"threonine." The Columbia Encyclopedia, 6th ed.. . Retrieved August 23, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/threonine

threonine

threonine An essential amino acid. It was the last of the protein amino acids to be discovered, in 1935, in studies of nitrogen balance on subjects fed mixtures of the then known amino acids in place of proteins.

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"threonine." A Dictionary of Food and Nutrition. . Encyclopedia.com. 23 Aug. 2017 <http://www.encyclopedia.com>.

"threonine." A Dictionary of Food and Nutrition. . Encyclopedia.com. (August 23, 2017). http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/threonine

"threonine." A Dictionary of Food and Nutrition. . Retrieved August 23, 2017 from Encyclopedia.com: http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/threonine

threonine

threonine (three-ŏ-neen) n. an essential amino acid. See also amino acid.

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"threonine." A Dictionary of Nursing. . Encyclopedia.com. 23 Aug. 2017 <http://www.encyclopedia.com>.

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threonine

threonine An aliphatic, polar (see POLAR MOLECULE) alpha-amino acid.

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"threonine." A Dictionary of Plant Sciences. . Encyclopedia.com. 23 Aug. 2017 <http://www.encyclopedia.com>.

"threonine." A Dictionary of Plant Sciences. . Encyclopedia.com. (August 23, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/threonine

"threonine." A Dictionary of Plant Sciences. . Retrieved August 23, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/threonine

threonine

threonine An aliphatic, polar, alpha amino acid.

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"threonine." A Dictionary of Zoology. . Encyclopedia.com. 23 Aug. 2017 <http://www.encyclopedia.com>.

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threonine

threonine See amino acid.

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"threonine." A Dictionary of Biology. . Encyclopedia.com. 23 Aug. 2017 <http://www.encyclopedia.com>.

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"threonine." A Dictionary of Biology. . Retrieved August 23, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/threonine-1