tryptophan

n. (Biochemistry) type of aromatic amino acid which is essential to nutrition in animals (found in some leguminous plant seeds)

Tryptophan (abbreviated as Trp or W) is an essential amino acid involved in human nutrition. It is one of the 20 amino acids encoded by the genetic code (as codon UGG). Only the L-stereoisomer appears in mammalian protein, but the D-stereoisomer is occasionally found in natural materials (for example, the marine venom peptide contryphan). A distinguishing structural characteristic of tryptophan is that it contains an indole functional group.
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Tryptophan /tryp·to·phan/ a naturally occurring amino acid, existing in proteins and essential for human metabolism. It is a precursor of serotonin. [more]Tryptophan - Community and Resources

Noun
1. an amino acid that occurs in proteins; is essential for growth and normal metabolism; a precursor of niacin
(synonym) tryptophane
(hypernym) essential amino acid

n. tryptophan, type of aromatic amino acid which is essential to nutrition in animals (Biochemistry)