/fen'l al"euh neen', -nin, feen'-/, n. Biochem.a crystalline, water-soluble, essential amino acid, C6H5CH2CH(NH2)COOH, necessary to the nutrition of humans and most animals, obtained chiefly from egg white or skim milk. Abbr.: Phe; Symbol: F Also called phenylaminopropionic acid /fen"l euh mee"noh proh pee on"ik, -am"euh noh-, feen"-, fen'l euh mee'noh-, -am'euh noh-, feen'-/.[1880-85; PHENYL + ALANINE]
* * *It is used in medicine and nutrition and as one of the two amino acids making up aspartame. Persons with phenylketonuria do not metabolize phenylalanine properly and must adhere to a diet free of it.
* * *an amino acid present in the mixture obtained upon hydrolysis of common proteins. Human hemoglobin (the oxygen-carrying pigment of red blood cells) is one of the richest sources of phenylalanine, yielding 9.6 percent by weight. First isolated in 1881 from lupine seedlings, phenylalanine is one of several essential amino acids for fowls and mammals; i.e., they cannot synthesize it and require dietary sources. Microorganisms synthesize it from glucose and pyruvic acid (products of the breakdown of carbohydrates).
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