"an amino acid that occurs in proteins; is essential for growth and normal metabolism; a precursor of niacin"@en-us . "0.125"^^ . . "0"^^ . "115081417"^^ . . . . . . . . "15081417-n"^^ . . . "an amino acid that occurs in proteins; is essential for growth and normal metabolism; a precursor of niacin"@en-us . "tryptophan"^^ . "tryptophan"@en-us . "110819527"@en-us . "114227036"@en-us . "tryptophane"@en-us .