ContaminantDB: L-Tryptophan

Identification Taxonomy Biological Properties Physical Properties Toxicity Profile Spectra Concentrations Links References Targets (7)XML

Record Information

Version

1.0

Creation Date

2014-08-29 06:35:45 UTC

Update Date

2026-04-17 18:55:29 UTC

Accession Number

CHEM003329

Identification

Common Name

L-Tryptophan

Class

Small Molecule

Description

Tryptophan is an essential amino acid which is the precursor of serotonin. Serotonin is a brain neurotransmitter, platelet clotting factor and neurohormone found in organs throughout the body. Metabolism of tryptophan to serotonin requires nutrients such as vitamin B6, niacin and glutathione. Niacin is an important metabolite of tryptophan. High corn or other tryptophan-deficient diets can cause pellagra, which is a niacin-tryptophan deficiency disease with symptoms of dermatitis, diarrhea and dementia. Inborn errors of tryptophan metabolism exist where a tumor (carcinoid) makes excess serotonin. Hartnup's disease is a disease where tryptophan and other amino acids are not absorbed properly. Tryptophan supplements may be useful in each condition, in carcinoid replacing the over-metabolized nutrient and in Hartnup's supplementing a malabsorbed nutrient. Some disorders of excess tryptophan in the blood may contribute to mental retardation. Assessment of tryptophan deficiency is done through studying excretion of tryptophan metabolites in the urine or blood. Blood may be the most sensitive test because the amino acid tryptophan is transported in a unique way. Increased urination of tryptophan fragments correlates with increased tryptophan degradation, which occurs with oral contraception, depression, mental retardation, hypertension and anxiety states. The requirement for tryptophan and protein decreases with age. Adults' minimum daily requirement is 3 mg/kg/day or about 200 mg a day. This may be an underestimation, for there are 400 mg of tryptophan in just a cup of wheat germ. A cup of low fat cottage cheese contains 300 mg of tryptophan and chicken and turkey contain up to 600 mg per pound.

Contaminant Sources

Cosmetic Chemicals
EAFUS Chemicals
FooDB Chemicals
HMDB Contaminants - Feces
HMDB Contaminants - Urine
STOFF IDENT Compounds
T3DB toxins
ToxCast & Tox21 Chemicals

Contaminant Type

Amine
Amino Acid, Essential
Animal Toxin
Antidepressive Agent, Second-Generation
Dietary Supplement
Drug
Food Toxin
Metabolite
Micronutrient
Natural Compound
Nutraceutical
Organic Compound
Supplement

Chemical Structure

MOL SDF PDB SMILES InChI

Synonyms

Value	Source
(2S)-2-Amino-3-(1H-indol-3-yl)propanoic acid	ChEBI
(S)-alpha-Amino-1H-indole-3-propanoic acid	ChEBI
(S)-alpha-Amino-beta-(3-indolyl)-propionic acid	ChEBI
(S)-Tryptophan	ChEBI
L-(-)-Tryptophan	ChEBI
L-beta-3-Indolylalanine	ChEBI
Trp	ChEBI
Tryptophan	ChEBI
W	ChEBI
(2S)-2-Amino-3-(1H-indol-3-yl)propanoate	Generator
(S)-a-Amino-1H-indole-3-propanoate	Generator
(S)-a-Amino-1H-indole-3-propanoic acid	Generator
(S)-alpha-Amino-1H-indole-3-propanoate	Generator
(S)-Α-amino-1H-indole-3-propanoate	Generator
(S)-Α-amino-1H-indole-3-propanoic acid	Generator
(S)-a-Amino-b-(3-indolyl)-propionate	Generator
(S)-a-Amino-b-(3-indolyl)-propionic acid	Generator
(S)-alpha-Amino-beta-(3-indolyl)-propionate	Generator
(S)-Α-amino-β-(3-indolyl)-propionate	Generator
(S)-Α-amino-β-(3-indolyl)-propionic acid	Generator
L-b-3-Indolylalanine	Generator
L-Β-3-indolylalanine	Generator
(-)-Tryptophan	HMDB
(L)-Tryptophan	HMDB
(S)-1H-Indole-3-alanine	HMDB
(S)-2-Amino-3-(3-indolyl)propionic acid	HMDB
(S)-a-Amino-b-indolepropionate	HMDB
(S)-a-Amino-b-indolepropionic acid	HMDB
(S)-a-Aminoindole-3-propionate	HMDB
(S)-a-Aminoindole-3-propionic acid	HMDB
(S)-alpha-Amino-beta-indolepropionate	HMDB
(S)-alpha-Amino-beta-indolepropionic acid	HMDB
(S)-alpha-Aminoindole-3-propionate	HMDB
(S)-alpha-Aminoindole-3-propionic acid	HMDB
1-beta-3-Indolylalanine	HMDB
1beta-3-Indolylalanine	HMDB
1H-Indole-3-alanine	HMDB
2-Amino-3-indolylpropanoate	HMDB
2-Amino-3-indolylpropanoic acid	HMDB
3-(1H-indol-3-yl)-L-Alanine	HMDB
3-indol-3-Ylalanine	HMDB
Alpha'-amino-3-indolepropionic acid	HMDB
alpha-Aminoindole-3-propionic acid	HMDB
Ardeytropin	HMDB
H-TRP-OH	HMDB
Indole-3-alanine	HMDB
Kalma	HMDB
L-alpha-Amino-3-indolepropionic acid	HMDB
L-alpha-Aminoindole-3-propionic acid	HMDB
L-Tryptofan	HMDB
L-Tryptophane	HMDB
Lopac-T-0254	HMDB
Lyphan	HMDB
Optimax	HMDB
Pacitron	HMDB
Sedanoct	HMDB
Triptofano	HMDB
Trofan	HMDB
Tryptacin	HMDB
Tryptan	HMDB
Tryptophane	HMDB
Tryptophanum	HMDB
Ardeydorm	HMDB
L Tryptophan	HMDB
L-Tryptophan-ratiopharm	HMDB
Merck brand OF tryptophan	HMDB
Niddapharm brand OF tryptophan	HMDB
ICN brand OF tryptophan	HMDB
Levotryptophan	HMDB
PMS Tryptophan	HMDB
PMS-Tryptophan	HMDB
Ratiopharm brand OF tryptophan	HMDB
Esparma brand OF tryptophan	HMDB
Ratio-tryptophan	HMDB
L Tryptophan ratiopharm	HMDB
Naturruhe	HMDB
Tryptophan metabolism alterations	HMDB
Ardeypharm brand OF tryptophan	HMDB
Kalma brand OF tryptophan	HMDB
Pharmascience brand OF tryptophan	HMDB
Upsher-smith brand OF tryptophan	HMDB
Ratio tryptophan	HMDB

Chemical Formula

C₁₁H₁₂N₂O₂

Average Molecular Mass

204.225 g/mol

Monoisotopic Mass

204.090 g/mol

CAS Registry Number

73-22-3

IUPAC Name

(2S)-2-amino-3-(1H-indol-3-yl)propanoic acid

Traditional Name

L-tryptophan

SMILES

N[C@@H](CC1=CNC2=CC=CC=C12)C(O)=O

InChI Identifier

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

InChI Key

QIVBCDIJIAJPQS-VIFPVBQESA-N

Chemical Taxonomy

Description

belongs to the class of organic compounds known as indolyl carboxylic acids and derivatives. Indolyl carboxylic acids and derivatives are compounds containing a carboxylic acid chain (of at least 2 carbon atoms) linked to an indole ring.

Kingdom

Organic compounds

Super Class

Organoheterocyclic compounds

Class

Indoles and derivatives

Sub Class

Indolyl carboxylic acids and derivatives

Direct Parent

Indolyl carboxylic acids and derivatives

Alternative Parents

Substituents

Indolyl carboxylic acid derivative
Alpha-amino acid
Alpha-amino acid or derivatives
L-alpha-amino acid
3-alkylindole
Indole
Aralkylamine
Benzenoid
Substituted pyrrole
Heteroaromatic compound
Pyrrole
Amino acid or derivatives
Amino acid
Carboxylic acid derivative
Carboxylic acid
Monocarboxylic acid or derivatives
Azacycle
Amine
Primary aliphatic amine
Hydrocarbon derivative
Organic oxide
Organic oxygen compound
Organic nitrogen compound
Carbonyl group
Organonitrogen compound
Organooxygen compound
Primary amine
Organopnictogen compound
Aromatic heteropolycyclic compound

Molecular Framework

Aromatic heteropolycyclic compounds

External Descriptors

proteinogenic amino acid (CHEBI:16828 )
L-alpha-amino acid (CHEBI:16828 )
tryptophan (CHEBI:16828 )
erythrose 4-phosphate/phosphoenolpyruvate family amino acid (CHEBI:16828 )
Common amino acids (C00078 )

Biological Properties

Status

Detected and Not Quantified

Origin

Endogenous

Cellular Locations

Cytoplasm
Extracellular

Biofluid Locations

Not Available

Tissue Locations

Fibroblasts
Nerve Cells
Prostate

Pathways

Name	SMPDB Link	KEGG Link
Transcription/Translation	SMP00019	Not Available
Tryptophan Metabolism	SMP00063	map00380
Hartnup Disorder	SMP00189	Not Available

Applications

Biological Roles

Chemical Roles

Not Available

Physical Properties

State

Solid

Appearance

White powder.

Experimental Properties

Property	Value
Melting Point	290.5 dec°C
Boiling Point	Not Available
Solubility	1.34E+004 mg/L (at 25°C)

Predicted Properties

Property	Value	Source
Water Solubility	1.36 g/L	ALOGPS
logP	-1.1	ALOGPS
logP	-1.1	ChemAxon
logS	-2.2	ALOGPS
pKa (Strongest Acidic)	2.54	ChemAxon
pKa (Strongest Basic)	9.4	ChemAxon
Physiological Charge	0	ChemAxon
Hydrogen Acceptor Count	3	ChemAxon
Hydrogen Donor Count	3	ChemAxon
Polar Surface Area	79.11 Å²	ChemAxon
Rotatable Bond Count	3	ChemAxon
Refractivity	56.2 m³·mol⁻¹	ChemAxon
Polarizability	21.05 Å³	ChemAxon
Number of Rings	2	ChemAxon
Bioavailability	1	ChemAxon
Rule of Five	Yes	ChemAxon
Ghose Filter	No	ChemAxon
Veber's Rule	No	ChemAxon
MDDR-like Rule	No	ChemAxon

Spectra

Spectrum Type	Description	Splash Key	View
GC-MS	GC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (3 TMS)	splash10-0udi-0190000000-feaec8547634dddcad8c	Spectrum
GC-MS	GC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (3 TMS)	splash10-0udi-0390000000-45a6c4fd79081597d44a	Spectrum
GC-MS	GC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (Non-derivatized)	splash10-0udi-0290000000-34f7274f31a4cb321a0b	Spectrum
GC-MS	GC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (3 TMS)	splash10-0fk9-9270000000-9761607cbe821f87f172	Spectrum
GC-MS	GC-MS Spectrum - GC-MS (1 TMS)	splash10-001i-0900000000-3faeed7ad32e1755c03c	Spectrum
GC-MS	GC-MS Spectrum - GC-MS (3 TMS)	splash10-0udi-0290000000-9c57a732e337fade3cb6	Spectrum
GC-MS	GC-MS Spectrum - EI-B (Non-derivatized)	splash10-001i-0900000000-d054a214c1717940989f	Spectrum
GC-MS	GC-MS Spectrum - EI-B (Non-derivatized)	splash10-0udi-0290000000-9860799c854e5c9ac1c7	Spectrum
GC-MS	GC-MS Spectrum - GC-EI-TOF (Non-derivatized)	splash10-0udi-0190000000-feaec8547634dddcad8c	Spectrum
GC-MS	GC-MS Spectrum - GC-EI-TOF (Non-derivatized)	splash10-0udi-0390000000-45a6c4fd79081597d44a	Spectrum
GC-MS	GC-MS Spectrum - GC-EI-TOF (Non-derivatized)	splash10-0udi-0290000000-34f7274f31a4cb321a0b	Spectrum
GC-MS	GC-MS Spectrum - GC-EI-QQ (Non-derivatized)	splash10-0udi-3729000000-86129db57aaf1a245f93	Spectrum
GC-MS	GC-MS Spectrum - GC-EI-TOF (Non-derivatized)	splash10-0fk9-9270000000-9761607cbe821f87f172	Spectrum
GC-MS	GC-MS Spectrum - GC-MS (Non-derivatized)	splash10-001i-0900000000-3faeed7ad32e1755c03c	Spectrum
GC-MS	GC-MS Spectrum - GC-MS (Non-derivatized)	splash10-0udi-0290000000-9c57a732e337fade3cb6	Spectrum
Predicted GC-MS	Predicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positive	splash10-0560-4900000000-fa932bc4cffed0ca66b7	Spectrum
Predicted GC-MS	Predicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positive	splash10-00e9-9560000000-6829a8b2a2096883999f	Spectrum
Predicted GC-MS	Predicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positive	Not Available	Spectrum
Predicted GC-MS	Predicted GC-MS Spectrum - GC-MS (TMS_1_2) - 70eV, Positive	Not Available	Spectrum
Predicted GC-MS	Predicted GC-MS Spectrum - GC-MS (TMS_1_3) - 70eV, Positive	Not Available	Spectrum
Predicted GC-MS	Predicted GC-MS Spectrum - GC-MS (TBDMS_1_1) - 70eV, Positive	Not Available	Spectrum
Predicted GC-MS	Predicted GC-MS Spectrum - GC-MS (TBDMS_1_2) - 70eV, Positive	Not Available	Spectrum
Predicted GC-MS	Predicted GC-MS Spectrum - GC-MS (TBDMS_1_3) - 70eV, Positive	Not Available	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - Quattro_QQQ 10V, Positive (Annotated)	splash10-000i-0910000000-db5439a5499b19881720	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - Quattro_QQQ 25V, Positive (Annotated)	splash10-014m-0900000000-cc4a579a29d19a1c0d44	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - Quattro_QQQ 40V, Positive (Annotated)	splash10-00kf-3900000000-a931a9df4c855603d06e	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positive	splash10-0a4i-0290000000-5fa576241f151a3a01a2	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positive	splash10-0002-0900000000-417ea0b6e4e18e5fbde1	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positive	splash10-000i-0900000000-38f5ce97d594f3e3f12d	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positive	splash10-000i-0900000000-783ffff22f31096f238f	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positive	splash10-0a4i-0290000000-3ced9d310dda312f8582	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positive	splash10-0002-0900000000-a050919a36b995d34553	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positive	splash10-000i-0900000000-1ddec73daead0ffadce4	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Positive	splash10-000i-0900000000-a8c9c60f075a675f6629	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negative	splash10-0udi-0290602010-c09c931538bff74ac400	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negative	splash10-0a4i-0900000000-0fed327c2a56f556e04c	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negative	splash10-0udi-0090000000-98ec1c2c012e58eab924	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negative	splash10-00di-0090000000-fc77784da5d9b288d751	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negative	splash10-0udi-0290601010-d6f94902c0cf639cb7bc	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negative	splash10-0a4i-0900000000-27633a4f7ecfac45c730	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negative	splash10-0udi-0090000000-ee6cb8392b2e8d644bc1	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-ITFT (LTQ Orbitrap XL, Thermo Scientfic) , Negative	splash10-004i-0090000000-d81c86eceee1c9824b02	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 10V, Negative	splash10-0udi-0190000000-0e8b883dc8ab06c89d77	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 20V, Negative	splash10-0uxu-2940000000-cb35b9680612e19d8b3a	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 30V, Negative	splash10-014i-2900000000-7cc592351cc616b1d75f	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 40V, Negative	splash10-014i-1900000000-987615a0add5eb2c3169	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 50V, Negative	splash10-014i-1900000000-f150d9d1e19c72d337a8	Spectrum
LC-MS/MS	LC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 10V, Positive	splash10-0a4r-0690000000-ea2d79df0b56be85abdd	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum
2D NMR	[1H,1H] 2D NMR Spectrum	Not Available	Spectrum
2D NMR	[1H,13C] 2D NMR Spectrum	Not Available	Spectrum

Toxicity Profile

Route of Exposure

Not Available

Mechanism of Toxicity

A number of important side reactions occur during the catabolism of tryptophan on the pathway to acetoacetate. The first enzyme of the catabolic pathway is an iron porphyrin oxygenase that opens the indole ring. The latter enzyme is highly inducible, its concentration rising almost 10-fold on a diet high in tryptophan. Kynurenine is the first key branch point intermediate in the pathway. Kynurenine undergoes deamniation in a standard transamination reaction yielding kynurenic acid. Kynurenic acid and metabolites have been shown to act as antiexcitotoxics and anticonvulsives. A second side branch reaction produces anthranilic acid plus alanine. Another equivalent of alanine is produced further along the main catabolic pathway, and it is the production of these alanine residues that allows tryptophan to be classified among the glucogenic and ketogenic amino acids. The second important branch point converts kynurenine into 2-amino-3-carboxymuconic semialdehyde, which has two fates. The main flow of carbon elements from this intermediate is to glutarate. An important side reaction in liver is a transamination and several rearrangements to produce limited amounts of nicotinic acid, which leads to production of a small amount of NAD⁺ and NADP⁺.

Metabolism

Hepatic.

Toxicity Values

Not Available

Lethal Dose

Not Available

Carcinogenicity (IARC Classification)

No indication of carcinogenicity to humans (not listed by IARC).

Uses/Sources

Tryptophan may be useful in increasing serotonin production, promoting healthy sleep, managing depression by enhancing mental and emotional well-being, managing pain tolerance, and managing weight.

Minimum Risk Level

Not Available

Health Effects

Not Available

Symptoms

Symptoms of overdose include agitation, confusion, diarrhea, fever, overactive reflexes, poor coordination, restlessness, shivering, sweating, talking or acting with excitement you cannot control, trembling or shaking, twitching, and vomiting.

Treatment

Not Available

Concentrations

Not Available

External Links

DrugBank ID

DB00150

HMDB ID

HMDB0000929

FooDB ID

FDB002250

Phenol Explorer ID

Not Available

KNApSAcK ID

BiGG ID

BioCyc ID

METLIN ID

PDB ID

Not Available

Wikipedia Link

Chemspider ID

ChEBI ID

PubChem Compound ID

Kegg Compound ID

YMDB ID

ECMDB ID

References

Synthesis Reference

Sten Vilhelm Gatenbeck, Per Olof Hedman, “Fermentative process for the production of L-tryptophan and its derivatives.” U.S. Patent US3963572, issued April, 1974.

MSDS

Link

General References

1. Klein MS, Almstetter MF, Schlamberger G, Nurnberger N, Dettmer K, Oefner PJ, Meyer HH, Wiedemann S, Gronwald W: Nuclear magnetic resonance and mass spectrometry-based milk metabolomics in dairy cows during early and late lactation. J Dairy Sci. 2010 Apr;93(4):1539-50. doi: 10.3168/jds.2009-2563.

2. Mung D, Li L: Development of Chemical Isotope Labeling LC-MS for Milk Metabolomics: Comprehensive and Quantitative Profiling of the Amine/Phenol Submetabolome. Anal Chem. 2017 Apr 18;89(8):4435-4443. doi: 10.1021/acs.analchem.6b03737. Epub 2017 Mar 28.

3. Klein MS, Almstetter MF, Nurnberger N, Sigl G, Gronwald W, Wiedemann S, Dettmer K, Oefner PJ: Correlations between milk and plasma levels of amino and carboxylic acids in dairy cows. J Proteome Res. 2013 Nov 1;12(11):5223-32. doi: 10.1021/pr4006537. Epub 2013 Aug 23.

4. Mung D, Li L: Applying quantitative metabolomics based on chemical isotope labeling LC-MS for detecting potential milk adulterant in human milk. Anal Chim Acta. 2018 Feb 25;1001:78-85. doi: 10.1016/j.aca.2017.11.019. Epub 2017 Nov 14.

5. A. Foroutan et al. The Chemical Composition of Commercial Cow's Milk (in preparation)

6. Fooddata+, The Technical University of Denmark (DTU): https://frida.fooddata.dk/QueryFood.php?fn=milk&lang=en

7. Amir-Heidari, Bagher; Thirlway, Jenny; Micklefield, Jason. Stereochemical course of tryptophan dehydrogenation during biosynthesis of the calcium-dependent lipopeptide antibiotics. Organic Letters (2007), 9(8), 1513-1516.

8. Jonas AJ, Butler IJ: Circumvention of defective neutral amino acid transport in Hartnup disease using tryptophan ethyl ester. J Clin Invest. 1989 Jul;84(1):200-4.

9. Peng CT, Wu KH, Lan SJ, Tsai JJ, Tsai FJ, Tsai CH: Amino acid concentrations in cerebrospinal fluid in children with acute lymphoblastic leukemia undergoing chemotherapy. Eur J Cancer. 2005 May;41(8):1158-63. Epub 2005 Apr 14.