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phenylalanine
phenylalanine , 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 31 mg of this amino acid per day per kg (14 mg per lb) of body weight. Phenylalanine can be degraded into simpler compounds by the enzymes of the body and is readily converted to the amino acid tyrosine . Phenylketonuria (PKU), an inherited disease that, if left untreated, results in retarded mental development in children, has been shown to be associated with the lack of activity of the enzyme that converts phenylalanine to tyrosine. This results in the buildup of phenylalanine in the blood, an event leading to several pathological consequences. The incidence of this disease, about one in every 10,000 births, is high enough to have prompted several states to institute regular screening procedures for the detection of the disease in newborns. If diagnosed early the disease can be controlled to a great extent by administering a diet very low in phenylalanine. Phenylalanine contributes to the structure of proteins into which it has been incorporated by the tendency of its side chain to participate in hydrophobic interactions (see isoleucine ). This amino acid was first isolated from a natural source (lupine sprouts) in 1879; it was first chemically synthesized in 1882. |
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"phenylalanine." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 29 May. 2012 <http://www.encyclopedia.com>. "phenylalanine." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 29, 2012). http://www.encyclopedia.com/doc/1E1-phenylal.html "phenylalanine." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 29, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-phenylal.html |
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phenylalanine
phen·yl·al·a·nine / ˌfenəlˈaləˌnēn; ˌfēnəl-/ • n. Biochem. an amino acid, C6H5CH2CH(NH2)COOH, widely distributed in plant proteins. It is an essential nutrient in the diet of vertebrates. |
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"phenylalanine." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 29 May. 2012 <http://www.encyclopedia.com>. "phenylalanine." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 29, 2012). http://www.encyclopedia.com/doc/1O999-phenylalanine.html "phenylalanine." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 29, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-phenylalanine.html |
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phenylalanine
phenylalanine An essential amino acid; in addition to its role in protein synthesis, it is the metabolic precursor of tyrosine (and hence noradrenaline, adrenaline, and the thyroid hormones). Dietary tyrosine spares phenylalanine, so reducing the requirement.
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DAVID A. BENDER. "phenylalanine." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. 29 May. 2012 <http://www.encyclopedia.com>. DAVID A. BENDER. "phenylalanine." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. (May 29, 2012). http://www.encyclopedia.com/doc/1O39-phenylalanine.html DAVID A. BENDER. "phenylalanine." A Dictionary of Food and Nutrition. 2005. Retrieved May 29, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O39-phenylalanine.html |
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phenylalanine
phenylalanine (fee-nyl-al-ă-neen) n. an essential amino acid that is readily converted to tyrosine. Blockade of this metabolic pathway gives rise to phenylketonuria.
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"phenylalanine." A Dictionary of Nursing. 2008. Encyclopedia.com. 29 May. 2012 <http://www.encyclopedia.com>. "phenylalanine." A Dictionary of Nursing. 2008. Encyclopedia.com. (May 29, 2012). http://www.encyclopedia.com/doc/1O62-phenylalanine.html "phenylalanine." A Dictionary of Nursing. 2008. Retrieved May 29, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-phenylalanine.html |
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phenylalanine
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MICHAEL ALLABY. "phenylalanine." A Dictionary of Zoology. 1999. Encyclopedia.com. 29 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "phenylalanine." A Dictionary of Zoology. 1999. Encyclopedia.com. (May 29, 2012). http://www.encyclopedia.com/doc/1O8-phenylalanine.html MICHAEL ALLABY. "phenylalanine." A Dictionary of Zoology. 1999. Retrieved May 29, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-phenylalanine.html |
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phenylalanine
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MICHAEL ALLABY. "phenylalanine." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 29 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "phenylalanine." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (May 29, 2012). http://www.encyclopedia.com/doc/1O7-phenylalanine.html MICHAEL ALLABY. "phenylalanine." A Dictionary of Plant Sciences. 1998. Retrieved May 29, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-phenylalanine.html |
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phenylalanine
phenylalanine See amino acid.
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"phenylalanine." A Dictionary of Biology. 2004. Encyclopedia.com. 29 May. 2012 <http://www.encyclopedia.com>. "phenylalanine." A Dictionary of Biology. 2004. Encyclopedia.com. (May 29, 2012). http://www.encyclopedia.com/doc/1O6-phenylalanine.html "phenylalanine." A Dictionary of Biology. 2004. Retrieved May 29, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-phenylalanine.html |
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