Tryptophan
Skeletal formula of L-tryptophan | |||
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Names | |||
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IUPAC name
Tryptophan | |||
Systematic IUPAC name
(2S)-2-amino-3-(1H-indol-3-yl)propanoic acid | |||
Other names
2-Amino-3-(1H-indol-3-yl)propanoic acid | |||
Identifiers | |||
3D model (JSmol) |
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ChEBI | |||
ChEMBL | |||
ChemSpider | |||
DrugBank | |||
ECHA InfoCard | 100.000.723 | ||
KEGG | |||
PubChem CID |
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UNII | |||
CompTox Dashboard (EPA) |
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Properties | |||
C11H12N2O2 | |||
Molar mass | 204.229 g·mol−1 | ||
Soluble: 0.23 g/L at 0 °C, 11.4 g/L at 25 °C, | |||
Solubility | Soluble in hot alcohol, alkali hydroxides; insoluble in chloroform. | ||
Acidity (pKa) | 2.38 (carboxyl), 9.39 (amino) | ||
-132.0·10−6 cm3/mol | |||
Pharmacology | |||
N06AX02 (WHO) | |||
Supplementary data page | |||
Tryptophan (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references |
Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromatic beta carbon substituent. Tryptophan is also a precursor to the neurotransmitter serotonin, the hormone melatonin, and vitamin B3. It is encoded by the codon UGG.
Like other amino acids, tryptophan is a zwitterion at physiological pH where the amino group is protonated (–NH+
3; pKa = 9.39) and the carboxylic acid is deprotonated ( –COO−; pKa = 2.38).
Humans and many animals cannot synthesize tryptophan: they need to obtain it through their diet, making it an essential amino acid. In 2023, the emission spectrum of tryptophan was discovered in the interstellar gas of the star cluster IC 348.