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[tahy-ruh-seen, -sin, tir-uh-] /ˈtaɪ rəˌsin, -sɪn, ˈtɪr ə-/
noun, Biochemistry.
a crystalline amino acid, HOC 6 H 4 CH 2 CH(NH 2)COOH, abundant in ripe cheese, that acts as a precursor of norepinephrine and dopamine. Symbol: Y.
Abbreviation: Tyr;
Origin of tyrosine
1855-60; < Greek tȳrós cheese + -ine2 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for tyrosine
Historical Examples
  • Both the tyrosine and tryptophane may be either in the free state or in combination as polypeptid or peptone.

  • This reaction is caused by the tyrosine group (p. oxy α amido phenyl-propionic acid).

    Animal Proteins Hugh Garner Bennett
British Dictionary definitions for tyrosine


/ˈtaɪrəˌsiːn; -sɪn; ˈtɪrə-/
an aromatic nonessential amino acid; a component of proteins. It is a metabolic precursor of thyroxine, the pigment melanin, and other biologically important compounds
Word Origin
C19: from Greek turos cheese + -ine²
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for tyrosine

amino acid, 1857, coined 1846 by German chemist Baron von Justus Liebig (1802-1873), who had first obtained it a year before, from Greek tyros "cheese" + chemical suffix -ine (2). So called because it was easily obtained from old cheese.

Online Etymology Dictionary, © 2010 Douglas Harper
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tyrosine in Medicine

tyrosine ty·ro·sine (tī'rə-sēn')
Abbr. Tyr
A white crystalline amino acid that is derived from the hydrolysis of proteins such as casein and is a precursor of epinephrine, thyroxine, and melanin.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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tyrosine in Science
A nonessential amino acid. Chemical formula: C9H11NO3. See more at amino acid.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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