tyrosine

n. amino acid resulting from the breakdown of proteins (Biochemistry)

Tyrosine (abbreviated as Tyr or Y) or 4-hydroxyphenylalanine, is one of the 20 amino acids that are used by cells to synthesize proteins. It is a non-essential amino acid and it is found in large quantities in casein. The word "tyrosine" is from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese.As an amino acid, tyrosine has a phenol side-chain with a hydroxyl group. Upon the location of the hydroxyl group, there are three structural isomers of Tyr, namely para-Tyr (p-Tyr), meta-Tyr (m-Tyr) and ortho-Tyr (o-Tyr). Only the first isomer (p-Tyr) is produced from L-Phe by the Phe-hydroxylase enzyme. The other two isoforms, m-Tyr and o-Tyr, can be produced as a consequence of free-radical attack on Phe in states with increased oxidative stress.
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Tyrosine /ty·ro·sine/ a naturally occurring, nonessential amino acid present in most proteins; it is a product of phenylalanine metabolism and a [more]Tyrosine - Community and Resources

Noun
1. an amino acid found in most proteins; a precursor of several hormones
(hypernym) amino acid, aminoalkanoic acid

-amino-ß-p-hydroxyphenylpropionic acid.
A naturally occuring amino acid with a phenol group on its side chain.