93659 Sigma-Aldrich


BioUltra, ≥99.5% (NT)

Synonym: (S)-2-Amino-3-(3-indolyl)propionic acid, L-α-Amino-3-indolepropionic acid

  • CAS Number 73-22-3

  • Empirical Formula (Hill Notation) C11H12N2O2

  • Molecular Weight 204.23

  •  Beilstein/REAXYS Number 86197

  •  EC Number 200-795-6

  •  MDL number MFCD00064340

  •  eCl@ss 32160406

  •  PubChem Substance ID 57653570

  •  NACRES NA.26



Related Categories Allium cepa (Onion), Allium sativum (Garlic), Aloe Vera, Amino Acids, Amino acids,
Quality Level   100
product line   BioUltra
assay   ≥99.5% (NT)
form   powder or crystals
optical activity   [α]20/D −31.5±1°, c = 1% in H2O
application(s)   cell analysis: suitable
impurities   insoluble matter, passes filter test
ign. residue   ≤0.1%
loss   ≤0.1% loss on drying, 20 °C (HV)
color   white
mp   280-285 °C (dec.) (lit.)
solubility   0.5 M HCl: 0.1 g/mL at 20 °C, clear, colorless to faintly yellow
anion traces   chloride (Cl-): ≤50 mg/kg
  sulfate (SO42-): ≤50 mg/kg
cation traces   Al: ≤5 mg/kg
  As: ≤0.1 mg/kg
  Ba: ≤5 mg/kg
  Bi: ≤5 mg/kg
  Ca: ≤10 mg/kg
  Cd: ≤5 mg/kg
  Co: ≤5 mg/kg
  Cr: ≤5 mg/kg
  Cu: ≤5 mg/kg
  Fe: ≤5 mg/kg
  K: ≤50 mg/kg
  Li: ≤5 mg/kg
  Mg: ≤5 mg/kg
  Mn: ≤5 mg/kg
  Mo: ≤5 mg/kg
  Na: ≤50 mg/kg
  Ni: ≤5 mg/kg
  Pb: ≤5 mg/kg
  Sr: ≤5 mg/kg
  Zn: ≤5 mg/kg
absorption   cut-off at 326 nm in 0.5 M HCl at 0.5 M
SMILES string   N[C@@H](Cc1c[nH]c2ccccc12)C(O)=O
InChI   1S/C11H12N2O2/c12-9(11(14)15)5-7-6-13-10-4-2-1-3-8(7)10/h1-4,6,9,13H,5,12H2,(H,14,15)/t9-/m0/s1



L-Tryptophan has been used as a nutritional supplement to study its effect on the circadian clock of primary cell lines. It has also been used as a test amino acid aerosol to study the variation in the fluorescence intensity of thermally-exposed bacterial bioaerosols.

Biochem/physiol Actions

Tryptophan (Trp) is one of the functional amino acids that are associated with growth, reproduction, maintenance and immunity. Increased Trp availability is necessary for the regulation of mood, cognition and behaviour. It is hypothesised that L-Trp might be useful in inducing sleep in healthy adults against the normal circadian rhythm. Trp uptake by the brain depends on the plasma ratio of Trp to all of the other LNAAs (large neutral amino acids). Higher the Trp:LNAAs ratio, greater is the Trp uptake.

Other Notes

Amino acid precursor of serotonin and melatonin

Tandem Mass Spectrometry data independently generated by Scripps Center for Metabolomics is available to view or download in PDF. 93659.pdf Tested metabolites are featured on Scripps Center for Metabolomics METLIN Metabolite Database. To learn more, visit

In tryptophan-substituted Sephadex® and Sepharose® for the improved chromatographic separation of cellulases; As spacer in isotachophoresis of serum proteins; Growth requirement of various microorganisms.

Legal Information

Sephadex is a registered trademark of Cytiva

Sepharose is a registered trademark of Cytiva

Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

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Protocols & Articles

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