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  • Chemical Name:L-Tryptophan
  • CAS No.:73-22-3
  • MF:C11H12N2O2
  • MW:204.23
  • Purity:>98% or As customer requested
  • Color:White to yellow-white
  • Product Categories: Biochemistry;Nutritional Supplements;L-Amino Acids;Amino Acids; APIs; Biochemical Engineering
  • Test method: HPLC


What is L-tryptophan?

Tryptophan is the least plentiful of all 22 amino acids and an essential amino acid in humans (provided by food), Tryptophan is found in most proteins and a precursor of serotonin. Tryptophan is converted to 5-hydroxy-tryptophan (5-HTP), converted in turn to serotonin, a neurotransmitter essential in regulating appetite, sleep, mood, and pain. Tryptophan is a natural sedative and present in dairy products, meats, brown rice, fish, and soybeans.

L-tryptophan is the L-enantiomer of tryptophan. It has a role as an antidepressant, a nutraceutical, a micronutrient, a plant metabolite, a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and a mouse metabolite. It is an erythrose 4-phosphate/phosphoenolpyruvate family amino acid, a proteinogenic amino acid, a tryptophan and a L-alpha-amino acid. It is a conjugate base of a L-tryptophanium. It is a conjugate acid of a L-tryptophanate. It is an enantiomer of a D-tryptophan. It is a tautomer of a L-tryptophan zwitterion. (Source: ChEBI)

Basic information   

Product Name: L-Tryptophan
Synonyms: Tryptophan; L-Tryptophane; Tryptophane; Tryptacin; L-Tryptophan(pharm grade); Pacitron; L-Tryptofan
CAS: 73-22-3
MF: C11H12N2O2
MW: 204.23
EINECS: 200-795-6
Product Categories: Biochemistry;Nutritional Supplements;L-Amino Acids;Amino Acids; APIs; Biochemical Engineering
Chemical Structure


Chemical Properties   

Melting point  289-290 °C (dec.)(lit.)
alpha  -31.1 º (c=1, H20)
Boiling point  342.72°C (rough estimate)
density  1.34
refractive index  -32 ° (C=1, H2O)
storage temp.  2-8°C
solubility  20% NH3: 0.1 g/mL at 20 °C, clear, colorless
pka 2.46(at 25℃)
form  powder
color  White to yellow-white
PH 5.5-7.0 (10g/l, H2O, 20℃)
optical activity [α]20/D 31.5±1°, c = 1% in H2O
Water Solubility  11.4 g/L (25 ºC)
Merck  14,9797
BRN  86197
Stability: Stable. Incompatible with strong acids, strong oxidizing agents.
Usage And Synthesis

L-Tryptophan Uses         

Amino acids-type drug:
It can be used in amino acid infusion, being often combined with iron and vitamins. Its co-administration with VB6 can improve depression and prevention/treatment of skin disease; as a sleep sedative, it can be combined with L-dopa for the treatment of Parkinson’s disease. It is carcinogenic to experimental animals; it may cause adverse reactions including nausea, anorexia and asthmas. Avoid combination with monoamine oxidase inhibitors.
Nutritional supplements:

Tryptophan contained in egg white protein, fish meat, corn meal and other amino acids are limited; content in cereals such as rice is also low. It can be combined with lysine, methionine and threonine for enhanced amino acids.

Technical Support & Resources

Information provided in the product description is from published literature. Due to the nature of scientific experimentation, your results (e.g., selectivity and effective concentrations) or specific application for this product may differ. If you have questions about how this product fits your application, please contact our technical support staff.

MSDS: MSDS available.

COA: COA can be available if you send us inquiry.

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Packaging and Shipping




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