ListMoto - Tryptophan

--- Advertisement ---

11.4 g/L at 25 °C, 17.1 g/L at 50 °C, 27.95 g/L at 75 °C

Solubility Soluble in hot alcohol, alkali hydroxides; insoluble in chloroform.

Acidity (pKa) 2.38 (carboxyl), 9.39 (amino)[1]

Magnetic susceptibility (χ)

-132.0·10−6 cm3/mol


ATC code

N06AX02 (WHO)

Supplementary data page

Structure and properties

Refractive index
Refractive index
(n), Dielectric constant
Dielectric constant
(εr), etc.

Thermodynamic data

Phase behaviour solid–liquid–gas

Spectral data


Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

N verify (what is YN ?)

Infobox references

(symbol Trp or W;[2] encoded by the codon UGG) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a non-polar aromatic amino acid. It is essential in humans, meaning the body cannot synthesize it: it must be obtained from the diet. Tryptophan
is also a precursor to the neurotransmitter serotonin and the hormone melatonin.[3] Like other amino acids, tryptophan is a zwitterion at physiological pH where the amino group is protonated (–NH3+; pKa = 9.39) and the carboxylic acid is deprotonated ( –COO−; pKa = 2.38).[4]


1 Isolation 2 Biosynthesis
and industrial production 3 Function 4 Recommended dietary allowance 5 Dietary sources

5.1 Turkey meat
Turkey meat
and drowsiness

6 Use as a dietary supplement 7 Side effects 8 Interactions 9 Research

9.1 Fluorescence

10 Safety

10.1 Eosinophilia–myalgia syndrome

11 See also 12 References 13 Further reading 14 External links

Isolation[edit] The isolation of tryptophan was first reported by Frederick Hopkins
Frederick Hopkins
in 1901.[5] Hopkins recovered tryptophan from hydrolysed casein, recovering 4-8 g of tryptophan from 600 g of crude casein.[6] Biosynthesis
and industrial production[edit] As an essential amino acid, tryptophan is not synthesized from simpler substances in humans and other animals, so it needs to be present in the diet in the form of tryptophan-containing proteins. Plants and microorganisms commonly synthesize tryptophan from shikimic acid or anthranilate:[7] anthranilate condenses with phosphoribosylpyrophosphate (PRPP), generating pyrophosphate as a by-product. The ring of the ribose moiety is opened and subjected to reductive decarboxylation, producing indole-3-glycerol phosphate; this, in turn, is transformed into indole. In the last step, tryptophan synthase catalyzes the formation of tryptophan from indole and the amino acid serine.

The industrial production of tryptophan is also biosynthetic and is based on the fermentation of serine and indole using either wild-type or genetically modified bacteria such as B. amyloliquefaciens, B. subtilis, C. glutamicum or E. coli. These strains carry mutations that prevent the reuptake of aromatic amino acids or multiple/overexpressed trp operons. The conversion is catalyzed by the enzyme tryptophan synthase.[8][9][10] Function[edit]

Metabolism of L-tryptophan into serotonin and melatonin (left) and niacin (right). Transformed functional groups after each chemical reaction are highlighted in red.

Amino acids, including tryptophan, are used as building blocks in protein biosynthesis, and proteins are required to sustain life. Many animals (including humans) cannot synthesize tryptophan: they need to obtain it through their diet, making it an essential amino acid. Tryptophan
is among the less common amino acids found in proteins, but it plays important structural or functional roles whenever it occurs. For instance, tryptophan and tyrosine residues play special roles in "anchoring" membrane proteins within the cell membrane. In addition, tryptophan functions as a biochemical precursor for the following compounds (see also figure to the right):

(a neurotransmitter), synthesized by tryptophan hydroxylase.[11][12] Melatonin
(a neurohormone) is in turn synthesized from serotonin, via N-acetyltransferase and 5-hydroxyindole-O-methyltransferase enzymes.[13] Niacin, also known as vitamin B3, is synthesized from tryptophan via kynurenine and quinolinic acids.[14] Auxins (a class of phytohormones) are synthesized from tryptophan.[15]

The disorder fructose malabsorption causes improper absorption of tryptophan in the intestine, reduced levels of tryptophan in the blood,[16] and depression.[17] In bacteria that synthesize tryptophan, high cellular levels of this amino acid activate a repressor protein, which binds to the trp operon.[18] Binding of this repressor to the tryptophan operon prevents transcription of downstream DNA that codes for the enzymes involved in the biosynthesis of tryptophan. So high levels of tryptophan prevent tryptophan synthesis through a negative feedback loop, and when the cell's tryptophan levels go down again, transcription from the trp operon resumes. This permits tightly regulated and rapid responses to changes in the cell's internal and external tryptophan levels.

metabolism by human gastrointestinal microbiota (v · t · e)

Tryptophan Clostridium sporogenes Lacto- bacilli Tryptophanase- expressing bacteria IPA I3A Indole Liver Brain IPA I3A Indole Indoxyl sulfate AST-120 AhR Intestinal immune cells Intestinal epithelium PXR Mucosal homeostasis: ↓TNF-α ↑Junction protein- coding mRNAs L cell GLP-1 T J Neuroprotectant: ↓Activation of glial cells and astrocytes ↓ 4-Hydroxy-2-nonenal
levels ↓DNA damage –Antioxidant –Inhibits β-amyloid fibril formation Maintains mucosal reactivity: ↑IL-22 production Associated with vascular disease: ↑Oxidative stress ↑ Smooth muscle cell
Smooth muscle cell
proliferation ↑Aortic wall thickness and calcification Associated with chronic kidney disease: ↑Renal dysfunction –Uremic toxin Kidneys

This diagram shows the biosynthesis of bioactive compounds (indole and certain other derivatives) from tryptophan by bacteria in the gut.[19] Indole
is produced from tryptophan by bacteria that express tryptophanase.[19] Clostridium sporogenes
Clostridium sporogenes
metabolizes tryptophan into indole and subsequently 3-indolepropionic acid
3-indolepropionic acid
(IPA),[20] a highly potent neuroprotective antioxidant that scavenges hydroxyl radicals.[19][21][22] IPA binds to the pregnane X receptor (PXR) in intestinal cells, thereby facilitating mucosal homeostasis and barrier function.[19] Following absorption from the intestine and distribution to the brain, IPA confers a neuroprotective effect against cerebral ischemia and Alzheimer’s disease.[19] Lactobacillus
species metabolize tryptophan into indole-3-aldehyde (I3A) which acts on the aryl hydrocarbon receptor (AhR) in intestinal immune cells, in turn increasing interleukin-22 (IL-22) production.[19] Indole
itself triggers the secretion of glucagon-like peptide-1 (GLP-1) in intestinal L cells and acts as a ligand for AhR.[19] Indole
can also be metabolized by the liver into indoxyl sulfate, a compound that is toxic in high concentrations and associated with vascular disease and renal dysfunction.[19] AST-120 (activated charcoal), an intestinal sorbent that is taken by mouth, adsorbs indole, in turn decreasing the concentration of indoxyl sulfate in blood plasma.[19]

Recommended dietary allowance[edit] In 2002, the U.S. Institute of Medicine
Institute of Medicine
set a Recommended Dietary Allowance (RDA) of 5 mg/kg body weight/day of Tryptophan
for adults 19 years and over.[23] Dietary sources[edit]

This section's factual accuracy is disputed. Relevant discussion may be found on Talk:Tryptophan. Please help to ensure that disputed statements are reliably sourced. (December 2017) (Learn how and when to remove this template message)

is present in most protein-based foods or dietary proteins. It is particularly plentiful in chocolate, oats, dried dates, milk, yogurt, cottage cheese, red meat, eggs, fish, poultry, sesame, chickpeas, almonds, sunflower seeds, pumpkin seeds, buckwheat, spirulina, and peanuts. Contrary to the popular belief[24][25][26] that turkey contains an abundance of tryptophan, the tryptophan content in turkey is typical of poultry.[27]

(Trp) Content of Various Foods[27][28]

Food Tryptophan [g/100 g of food] Protein [g/100 g of food] Tryptophan/ Protein

Egg white, dried




spirulina, dried




cod, atlantic, dried




Soybeans, raw




Cheese, Parmesan








Cheese, cheddar




Sunflower seed




Pork, chop
























Lamb, chop




Perch, Atlantic




Chickpeas, raw








Wheat flour, white




Baking chocolate, unsweetened








Rice, white, medium-grain, cooked




Quinoa, uncooked




Quinoa, cooked




Potatoes, russet












Turkey meat
Turkey meat
and drowsiness[edit] See also: Postprandial somnolence
Postprandial somnolence
§ Turkey and tryptophan A common assertion in the US is that heavy consumption of turkey meat results in drowsiness, due to high levels of tryptophan contained in turkey.[24][26] However, the amount of tryptophan in turkey is comparable to that contained in other meats.[25][27] Drowsiness
after eating may be caused by other foods eaten with the turkey, particularly carbohydrates.[29] Ingestion of a meal rich in carbohydrates triggers the release of insulin.[30][31][32][33] Insulin in turn stimulates the uptake of large neutral branched-chain amino acids (BCAA), but not tryptophan, into muscle, increasing the ratio of tryptophan to BCAA in the blood stream. The resulting increased tryptophan ratio reduces competition at the large neutral amino acid transporter (which transports both BCAA and aromatic amino acids), resulting in more uptake of tryptophan across the blood–brain barrier into the cerebrospinal fluid (CSF).[34][35][33] Once in the CSF, tryptophan is converted into serotonin in the raphe nuclei by the normal enzymatic pathway.[36][31] The resultant serotonin is further metabolised into melatonin by the pineal gland.[13] Hence, these data suggest that "feast-induced drowsiness"—or postprandial somnolence—may be the result of a heavy meal rich in carbohydrates, which indirectly increases the production of melatonin in the brain, and thereby promotes sleep.[36][30][31][32] Use as a dietary supplement[edit] Because tryptophan is converted into 5-hydroxytryptophan
(5-HTP) which is then converted into the neurotransmitter serotonin, it has been proposed that consumption of tryptophan or 5-HTP
may improve depression symptoms by increasing the level of serotonin in the brain. Tryptophan
is sold over the counter in the United States
United States
(after being banned to varying extents between 1989 and 2005) and the United Kingdom as a dietary supplement for use as an antidepressant, anxiolytic, and sleep aid. It is also marketed as a prescription drug in some European countries for the treatment of major depression. There is evidence that blood tryptophan levels are unlikely to be altered by changing the diet,[37][38] but consuming purified tryptophan increases the serotonin level in the brain, whereas eating foods containing tryptophan does not.[39] This is because the transport system that brings tryptophan across the blood–brain barrier also transports other amino acids which are contained in protein food sources.[40] High blood plasma levels of other large neutral amino acids prevent the plasma concentration of tryptophan from increasing brain concentration levels.[40] In 2001 a Cochrane review
Cochrane review
of the effect of 5-HTP
and tryptophan on depression was published. The authors included only studies of a high rigor and included both 5-HTP
and tryptophan in their review because of the limited data on either. Of 108 studies of 5-HTP
and tryptophan on depression published between 1966 and 2000, only two met the authors' quality standards for inclusion, totaling 64 study participants. The substances were more effective than placebo in the two studies included but the authors state that "the evidence was of insufficient quality to be conclusive" and note that "because alternative antidepressants exist which have been proven to be effective and safe, the clinical usefulness of 5-HTP
and tryptophan is limited at present".[41] The use of tryptophan as an adjunctive therapy in addition to standard treatment for mood and anxiety disorders is not supported by the scientific evidence.[42][41][42] Side effects[edit] Potential side effects of tryptophan supplementation include nausea, diarrhea, drowsiness, lightheadedness, headache, dry mouth, blurred vision, sedation, euphoria, and nystagmus (involuntary eye movements).[43][44] Interactions[edit] Tryptophan
taken as a dietary supplement (such as in tablet form) has the potential to cause serotonin syndrome when combined with antidepressants of the MAOI or SSRI class or other strongly serotonergic drugs.[44] Because tryptophan supplementation has not been thoroughly studied in a clinical setting, its interactions with other drugs are not well known.[41] Research[edit] In 1912 Felix Ehrlich demonstrated that yeast attacks the natural amino acids essentially by splitting off carbon dioxide and replacing the amino group with hydroxyl. By this reaction, tryptophan gives rise to tryptophol.[45] Tryptophan
affects brain serotonin synthesis when given orally in a purified form and is used to modify serotonin levels for research.[39] Low brain serotonin level is induced by administration of tryptophan-poor protein in a technique called "acute tryptophan depletion".[46] Studies using this method have evaluated the effect of serotonin on mood and social behavior, finding that serotonin reduces aggression and increases agreeableness.[47] Fluorescence[edit] Main article: Fluorescence spectroscopy § Tryptophan fluorescence Tryptophan
is an important intrinsic fluorescent probe (amino acid), which can be used to estimate the nature of the microenvironment around the tryptophan residue. Most of the intrinsic fluorescence emissions of a folded protein are due to excitation of tryptophan residues. Safety[edit] Eosinophilia–myalgia syndrome[edit] Main article: Eosinophilia–myalgia syndrome There was a large outbreak of eosinophilia-myalgia syndrome (EMS) in the U.S. in 1989, with more than 1,500 cases reported to the CDC and at least 37 deaths.[48] After preliminary investigation revealed that the outbreak was linked to intake of tryptophan, the U.S. Food and Drug Administration (FDA) recalled tryptophan supplements in 1989 and banned most public sales in 1990,[49][50][51] with other countries following suit.[52][53] Subsequent epidemiological studies suggested that EMS was linked to specific batches of L-tryptophan supplied by a single large Japanese manufacturer, Showa Denko.[49][54][55][56] It eventually became clear that recent batches of Showa Denko's L-tryptophan were contaminated by trace impurities, which were subsequently thought to be responsible for the 1989 EMS outbreak.[49][57][58] However, other evidence suggests that tryptophan itself may be a potentially major contributory factor in EMS.[59] The FDA loosened its restrictions on sales and marketing of tryptophan in February 2001,[49] but continued to limit the importation of tryptophan not intended for an exempted use until 2005.[60] The fact that the Showa Denko
Showa Denko
facility used genetically engineered bacteria to produce the contaminated batches of L-tryptophan later found to have caused the outbreak of eosinophilia-myalgia syndrome has been cited as evidence of a need for "close monitoring of the chemical purity of biotechnology-derived products".[61] Those calling for purity monitoring have, in turn, been criticized as anti-GMO activists who overlook possible non-GMO causes of contamination and threaten the development of biotech.[62] See also[edit]

5-HTP Acree-Rosenheim reaction Adamkiewicz reaction attenuator (genetics) dimethyltryptamine Hopkins Cole reaction serotonin tryptamine


^ Dawson RM, et al. (1969). Data for Biochemical Research. Oxford: Clarendon Press. ISBN 0-19-855338-2.  ^ "Nomenclature and Symbolism for Amino Acids and Peptides". IUPAC-IUB Joint Commission on Biochemical Nomenclature. 1983. Archived from the original on October 9, 2008. Retrieved March 5, 2018.  ^ Slominski A, Semak I, Pisarchik A, Sweatman T, Szczesniewski A, Wortsman J (2002). "Conversion of L-tryptophan to serotonin and melatonin in human melanoma cells". FEBS Letters. 511 (1-3): 102–6. doi:10.1016/s0014-5793(01)03319-1. PMID 11821057.  ^ "L-tryptophan C11H12N2O2 - PubChem". pubchem.ncbi.nlm.nih.gov. Retrieved December 22, 2016.  ^ Hopkins FG, Cole SW (December 1901). "A contribution to the chemistry of proteids: Part I. A preliminary study of a hitherto undescribed product of tryptic digestion". The Journal of Physiology. 27 (4-5): 418–28. doi:10.1113/jphysiol.1901.sp000880. PMC 1540554 . PMID 16992614.  ^ Cox GJ, King H (1943). "L-Tryptophane". Org. Synth. 2: 612–616. doi:10.15227/orgsyn.010.0100.  ^ Radwanski ER, Last RL (1995). " Tryptophan
biosynthesis and metabolism: biochemical and molecular genetics". The Plant Cell. 7 (7): 921–34. doi:10.1105/tpc.7.7.921. PMC 160888 . PMID 7640526.  ^ Ikeda M (2002). " Amino acid
Amino acid
production processes". Advances in Biochemical Engineering/Biotechnology. Advances in Biochemical Engineering/Biotechnology. 79: 1–35. doi:10.1007/3-540-45989-8_1. ISBN 978-3-540-43383-5. PMID 12523387.  ^ Becker J, Wittmann C (2012). "Bio-based production of chemicals, materials and fuels - Corynebacterium glutamicum
Corynebacterium glutamicum
as versatile cell factory". Current Opinion in Biotechnology. 23 (4): 631–40. doi:10.1016/j.copbio.2011.11.012. PMID 22138494.  ^ Conrado RJ, Varner JD, DeLisa MP (2008). "Engineering the spatial organization of metabolic enzymes: mimicking nature's synergy". Current Opinion in Biotechnology. 19 (5): 492–9. doi:10.1016/j.copbio.2008.07.006. PMID 18725290.  ^ Fernstrom JD (1983). "Role of precursor availability in control of monoamine biosynthesis in brain". Physiological Reviews. 63 (2): 484–546. PMID 6132421.  ^ Schaechter JD, Wurtman RJ (1990). " Serotonin
release varies with brain tryptophan levels" (PDF). Brain Research. 532 (1-2): 203–10. doi:10.1016/0006-8993(90)91761-5. PMID 1704290.  ^ a b Wurtman RJ, Anton-Tay F (1969). "The mammalian pineal as a neuroendocrine transducer" (PDF). Recent Progress in Hormone
Research. 25: 493–522. doi:10.1016/b978-0-12-571125-8.50014-4. PMID 4391290.  ^ Ikeda M, Tsuji H, Nakamura S, Ichiyama A, Nishizuka Y, Hayaishi O (1965). "Studies on the biosynthesis of nicotinamide adenine dinucleotide. II. A role of picolinic carboxylase in the biosynthesis of nicotinamide adenine dinucleotide from tryptophan in mammals". The Journal of Biological Chemistry. 240 (3): 1395–401. PMID 14284754.  ^ Palme K, Nagy F (2008). "A new gene for auxin synthesis". Cell. 133 (1): 31–2. doi:10.1016/j.cell.2008.03.014. PMID 18394986.  ^ Ledochowski M, Widner B, Murr C, Sperner-Unterweger B, Fuchs D (2001). " Fructose malabsorption
Fructose malabsorption
is associated with decreased plasma tryptophan" (PDF). Scandinavian Journal of Gastroenterology. 36 (4): 367–71. doi:10.1080/003655201300051135. PMID 11336160.  ^ Ledochowski M, Sperner-Unterweger B, Widner B, Fuchs D (June 1998). " Fructose malabsorption
Fructose malabsorption
is associated with early signs of mental depression". European Journal of Medical Research. 3 (6): 295–8. PMID 9620891.  ^ Gollnick P, Babitzke P, Antson A, Yanofsky C (2005). "Complexity in regulation of tryptophan biosynthesis in Bacillus subtilis". Annual Review of Genetics. 39: 47–68. doi:10.1146/annurev.genet.39.073003.093745. PMID 16285852.  ^ a b c d e f g h i Zhang LS, Davies SS (April 2016). "Microbial metabolism of dietary components to bioactive metabolites: opportunities for new therapeutic interventions". Genome Med. 8 (1): 46. doi:10.1186/s13073-016-0296-x. PMC 4840492 . PMID 27102537. Lactobacillus
spp. convert tryptophan to indole-3-aldehyde (I3A) through unidentified enzymes [125]. Clostridium sporogenes
Clostridium sporogenes
convert tryptophan to IPA [6], likely via a tryptophan deaminase. ... IPA also potently scavenges hydroxyl radicals  Table 2: Microbial metabolites: their synthesis, mechanisms of action, and effects on health and disease Figure 1: Molecular mechanisms of action of indole and its metabolites on host physiology and disease ^ Wikoff WR, Anfora AT, Liu J, Schultz PG, Lesley SA, Peters EC, Siuzdak G (March 2009). "Metabolomics analysis reveals large effects of gut microflora on mammalian blood metabolites". Proc. Natl. Acad. Sci. U.S.A. 106 (10): 3698–3703. doi:10.1073/pnas.0812874106. PMC 2656143 . PMID 19234110. Production of IPA was shown to be completely dependent on the presence of gut microflora and could be established by colonization with the bacterium Clostridium sporogenes.  IPA metabolism diagram ^ "3-Indolepropionic acid". Human Metabolome Database. University of Alberta. Retrieved 12 October 2015. Indole-3-propionate (IPA), a deamination product of tryptophan formed by symbiotic bacteria in the gastrointestinal tract of mammals and birds. 3-Indolepropionic acid has been shown to prevent oxidative stress and death of primary neurons and neuroblastoma cells exposed to the amyloid beta-protein in the form of amyloid fibrils, one of the most prominent neuropathologic features of Alzheimer's disease. 3-Indolepropionic acid
3-Indolepropionic acid
also shows a strong level of neuroprotection in two other paradigms of oxidative stress. (PMID 10419516 ) Origin:  • Endogenous  • Microbial  ^ Chyan YJ, Poeggeler B, Omar RA, Chain DG, Frangione B, Ghiso J, Pappolla MA (July 1999). "Potent neuroprotective properties against the Alzheimer beta-amyloid by an endogenous melatonin-related indole structure, indole-3-propionic acid". J. Biol. Chem. 274 (31): 21937–21942. doi:10.1074/jbc.274.31.21937. PMID 10419516. [Indole-3-propionic acid (IPA)] has previously been identified in the plasma and cerebrospinal fluid of humans, but its functions are not known. ... In kinetic competition experiments using free radical-trapping agents, the capacity of IPA to scavenge hydroxyl radicals exceeded that of melatonin, an indoleamine considered to be the most potent naturally occurring scavenger of free radicals. In contrast with other antioxidants, IPA was not converted to reactive intermediates with pro-oxidant activity.  ^ Institute of Medicine
Institute of Medicine
(2002). " Protein
and Amino Acids". Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press. pp. 589–768.  ^ a b Helmenstine AM. "Does Eating Turkey Make You Sleepy?". About.com. Retrieved 2013-11-13.  ^ a b Ballantyne C (2007-11-21). "Does Turkey Make You Sleepy?". Scientific American. Retrieved 2013-06-06.  ^ a b McCue K. "Chemistry.org: Thanksgiving, Turkey, and Tryptophan". Archived from the original on 2007-04-04. Retrieved 2007-08-17.  ^ a b c Holden, Joanne. "USDA National Nutrient Database for Standard Reference, Release 22". Nutrient Data Laboratory, Agricultural Research Service, United States
United States
Department of Agriculture. Retrieved November 29, 2009.  ^ Rambali B, Van Andel I, Schenk E, Wolterink G, van de Werken G, Stevenson H, Vleeming W (2002). "[The contribution of cocoa additive to cigarette smoking addiction]" (PDF). RIVM. The National Institute for Public Health and the Environment (Netherlands) (report 650270002/2002).  ^ "Food & mood. (neuroscience professor Richard Wurtman) (Interview)". Nutrition Action Healthletter. HighBeam Research. September 1992.  ^ a b Lyons PM, Truswell AS (March 1988). " Serotonin
precursor influenced by type of carbohydrate meal in healthy adults" (PDF). The American Journal of Clinical Nutrition. 47 (3): 433–9. PMID 3279747.  ^ a b c Wurtman RJ, Wurtman JJ, Regan MM, McDermott JM, Tsay RH, Breu JJ (January 2003). "Effects of normal meals rich in carbohydrates or proteins on plasma tryptophan and tyrosine ratios". The American Journal of Clinical Nutrition. 77 (1): 128–32. PMID 12499331.  ^ a b Afaghi A, O'Connor H, Chow CM (February 2007). "High-glycemic-index carbohydrate meals shorten sleep onset". The American Journal of Clinical Nutrition. 85 (2): 426–30. PMID 17284739.  ^ a b Banks WA, Owen JB, Erickson MA (2012). " Insulin
in the Brain: There and Back Again". Pharmacology & Therapeutics. 136 (1): 82–93. doi:10.1016/j.pharmthera.2012.07.006. ISSN 0163-7258. PMC 4134675 . PMID 22820012.  ^ Pardridge WM, Oldendorf WH (August 1975). "Kinetic analysis of blood-brain barrier transport of amino acids". Biochimica et Biophysica Acta. 401 (1): 128–36. doi:10.1016/0005-2736(75)90347-8. PMID 1148286.  ^ Maher TJ, Glaeser BS, Wurtman RJ (May 1984). "Diurnal variations in plasma concentrations of basic and neutral amino acids and in red cell concentrations of aspartate and glutamate: effects of dietary protein intake". The American Journal of Clinical Nutrition. 39 (5): 722–9. PMID 6538743.  ^ a b Fernstrom JD, Wurtman RJ (1971). "Brain serotonin content: increase following ingestion of carbohydrate diet". Science. 174 (4013): 1023–5. doi:10.1126/science.174.4013.1023. PMID 5120086.  ^ Soh NL, Walter GT (2011). " Tryptophan
and depression: can diet alone be the answer?". Acta Neuropsychiatrica VL. 23 (1): 1601–5215;. doi:10.1111/j.1601-5215.2010.00508.x.  ^ Fernstrom JD (2012). "Effects and side effects associated with the non-nutritional use of tryptophan by humans". The Journal of Nutrition. 142 (12): 2236S–2244S. doi:10.3945/jn.111.157065. PMID 23077193.  ^ a b Wurtman RJ, Hefti F, Melamed E (1980). "Precursor control of neurotransmitter synthesis". Pharmacological Reviews. 32 (4): 315–35. PMID 6115400.  ^ a b Henderson HE, Devlin R, Peterson J, Brunzell JD, Hayden MR (1990). "Frameshift mutation in exon 3 of the lipoprotein lipase gene causes a premature stop codon and lipoprotein lipase deficiency". Molecular Biology & Medicine. 7 (6): 511–7. PMID 2077351.  ^ a b c Shaw K, Turner J, Del Mar C (2002). Shaw KA, ed. "Tryptophan and 5-hydroxytryptophan
for depression". The Cochrane Database of Systematic Reviews (1): CD003198. doi:10.1002/14651858.CD003198. PMID 11869656.  ^ a b Ravindran AV, da Silva TL (September 2013). "Complementary and alternative therapies as add-on to pharmacotherapy for mood and anxiety disorders: a systematic review". Journal of Affective Disorders. 150 (3): 707–19. doi:10.1016/j.jad.2013.05.042. PMID 23769610.  ^ Kimura T, Bier DM, Taylor CL (December 2012). "Summary of workshop discussions on establishing upper limits for amino acids with specific attention to available data for the essential amino acids leucine and tryptophan". The Journal of Nutrition. 142 (12): 2245S–2248S. doi:10.3945/jn.112.160846. PMID 23077196.  ^ a b Howland RH (June 2012). " Dietary supplement
Dietary supplement
drug therapies for depression". Journal of Psychosocial Nursing and Mental Health Services. 50 (6): 13–6. doi:10.3928/02793695-20120508-06. PMID 22589230.  ^ Jackson RW (1930). "A synthesis of tryptophol" (PDF). Journal of Biological Chemistry. 88 (3): 659–662.  ^ Young SN (September 2013). "Acute tryptophan depletion in humans: a review of theoretical, practical and ethical aspects". Journal of Psychiatry & Neuroscience. 38 (5): 294–305. doi:10.1503/jpn.120209. PMC 3756112 . PMID 23428157.  ^ Young SN (2013). "The effect of raising and lowering tryptophan levels on human mood and social behaviour". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 368 (1615): 20110375. doi:10.1098/rstb.2011.0375. PMC 3638380 . PMID 23440461.  ^ Allen, J.A.; Varga, J (2014). "Eosinophilia–Myalgia Syndrome". In Wexler, Philip. Encyclopedia of Toxicology (3rd ed.). Burlington: Elsevier Science. ISBN 978-0-12-386455-0.  ^ a b c d "Information Paper on L-tryptophan and 5-hydroxy-L-tryptophan". FU. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Nutritional Products, Labeling, and Dietary Supplements. 2001-02-01. Archived from the original on 2005-02-25. Retrieved 2012-02-08.  ^ "L-tryptophan: Uses and Risks". WebMD. 2017-05-12. Retrieved 2017-06-05.  ^ Altman, Lawrence K. (27 April 1990). "Studies Tie Disorder to Maker of Food Supplement". The New York Times.  ^ Castot, A; Bidault, I; Bournerias, I; Carlier, P; Efthymiou, ML (1991). "["Eosinophilia-myalgia" syndrome due to L-tryptophan containing products. Cooperative evaluation of French Regional Centers of Pharmacovigilance. Analysis of 24 cases]". Therapie. 46 (5): 355–65. PMID 1754978.  ^ "COT Statement On Tryptophan
and the Eosinophilia-Myalgia Syndrome" (PDF). UK Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment. June 2004.  ^ Slutsker L, Hoesly FC, Miller L, Williams LP, Watson JC, Fleming DW (July 1990). " Eosinophilia-myalgia syndrome associated with exposure to tryptophan from a single manufacturer". JAMA. 264 (2): 213–7. doi:10.1001/jama.264.2.213. PMID 2355442.  ^ Back EE, Henning KJ, Kallenbach LR, Brix KA, Gunn RA, Melius JM (April 1993). "Risk factors for developing eosinophilia myalgia syndrome among L-tryptophan users in New York". The Journal of Rheumatology. 20 (4): 666–72. PMID 8496862.  ^ Kilbourne EM, Philen RM, Kamb ML, Falk H (October 1996). "Tryptophan produced by Showa Denko
Showa Denko
and epidemic eosinophilia-myalgia syndrome". The Journal of Rheumatology. Supplement. 46: 81–8; discussion 89–91. PMID 8895184.  ^ Mayeno AN, Lin F, Foote CS, Loegering DA, Ames MM, Hedberg CW, Gleich GJ (December 1990). "Characterization of "peak E," a novel amino acid associated with eosinophilia-myalgia syndrome". Science. 250 (4988): 1707–8. doi:10.1126/science.2270484. PMID 2270484.  ^ Ito J, Hosaki Y, Torigoe Y, Sakimoto K (January 1992). "Identification of substances formed by decomposition of peak E substance in tryptophan". Food and Chemical Toxicology. 30 (1): 71–81. doi:10.1016/0278-6915(92)90139-C. PMID 1544609.  ^ Smith MJ, Garrett RH (November 2005). "A heretofore undisclosed crux of eosinophilia-myalgia syndrome: compromised histamine degradation". Inflammation Research. 54 (11): 435–50. doi:10.1007/s00011-005-1380-7. PMID 16307217.  ^ Allen, JA; Peterson, A; Sufit, R; Hinchcliff, ME; Mahoney, JM; Wood, TA; Miller, FW; Whitfield, ML; Varga, J (November 2011). "Post-epidemic eosinophilia-myalgia syndrome associated with L-tryptophan". Arthritis and Rheumatism. 63 (11): 3633–9. doi:10.1002/art.30514. PMC 3848710 . PMID 21702023.  ^ Mayeno AN, Gleich GJ (September 1994). "Eosinophilia-myalgia syndrome and tryptophan production: a cautionary tale". Trends in Biotechnology. 12 (9): 346–52. doi:10.1016/0167-7799(94)90035-3. PMID 7765187.  ^ Raphals P (November 1990). "Does medical mystery threaten biotech?". Science. 250 (4981): 619. doi:10.1126/science.2237411. PMID 2237411. 

Further reading[edit]

Wood RM, Rilling JK, Sanfey AG, Bhagwagar Z, Rogers RD (May 2006). "Effects of tryptophan depletion on the performance of an iterated Prisoner's Dilemma game in healthy adults". Neuropsychopharmacology. 31 (5): 1075–84. doi:10.1038/sj.npp.1300932. PMID 16407905.  Sturtz R (2009). "what is the difference between L- Tryptophan
and 5-HTP?". The Lidtke letter: 1. 

External links[edit]

PATHWAY: Tryptophan
metabolism - Homo sapiens". KEGG: Kyoto Encyclopedia of Genes and Genomes. 2006-08-23. Retrieved 2008-04-20.  G. P. Moss. " Tryptophan
Catabolism (early stages)". Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 2008-04-20.  G. P. Moss. " Tryptophan
Catabolism (later stages)". Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 2008-04-20.  B. Mikkelson; D. P. Mikkelson (2007-11-22). "Turkey Causes Sleepiness". Urban Legends Reference Pages. Snopes.com. Retrieved 2008-04-20. 

v t e

The encoded amino acid

General topics

Protein Peptide Genetic code

By properties


Branched-chain amino acids
Branched-chain amino acids
(Valine Isoleucine Leucine) Methionine Alanine Proline Glycine


Phenylalanine Tyrosine Tryptophan Histidine

Polar, uncharged

Asparagine Glutamine Serine Threonine

Positive charge (pKa)

(≈10.8) Arginine
(≈12.5) Histidine

Negative charge (pKa)

Aspartic acid
Aspartic acid
(≈3.9) Glutamic acid
Glutamic acid
(≈4.1) Cysteine
(≈8.3) Tyrosine

Amino acids
Amino acids
types: Encoded (proteins) Essential Non-proteinogenic Ketogenic Glucogenic Imino acids D-amino acids Dehydroamino acids

v t e

Amino acid
Amino acid
metabolism metabolic intermediates



Saccharopine Allysine α-Aminoadipic acid α-Ketoadipate Glutaryl-CoA Glutaconyl-CoA Crotonyl-CoA β-Hydroxybutyryl-CoA


β-Hydroxy β-methylbutyric acid β-Hydroxy β-methylbutyryl-CoA Isovaleryl-CoA α-Ketoisocaproic acid β-Ketoisocaproic acid β-Ketoisocaproyl-CoA β-Leucine β-Methylcrotonyl-CoA β-Methylglutaconyl-CoA β-Hydroxy β-methylglutaryl-CoA


N'-Formylkynurenine Kynurenine Anthranilic acid 3-Hydroxykynurenine 3-Hydroxyanthranilic acid 2-Amino-3-carboxymuconic semialdehyde 2-Aminomuconic semialdehyde 2-Aminomuconic acid Glutaryl-CoA




3-Phosphoglyceric acid

glycine→creatine: Glycocyamine Phosphocreatine Creatinine

G→glutamate→ α-ketoglutarate


Urocanic acid Imidazol-4-one-5-propionic acid Formiminoglutamic acid Glutamate-1-semialdehyde


1-Pyrroline-5-carboxylic acid


Agmatine Ornithine Citrulline Cadaverine Putrescine


cysteine+glutamate→glutathione: γ-Glutamylcysteine

G→propionyl-CoA→ succinyl-CoA


α-Ketoisovaleric acid Isobutyryl-CoA Methacrylyl-CoA 3-Hydroxyisobutyryl-CoA 3-Hydroxyisobutyric acid 2-Methyl-3-oxopropanoic acid


2,3-Dihydroxy-3-methylpentanoic acid 2-Methylbutyryl-CoA Tiglyl-CoA 2-Methylacetoacetyl-CoA


generation of homocysteine: S-Adenosyl methionine S-Adenosyl-L-homocysteine Homocysteine

conversion to cysteine: Cystathionine alpha-Ketobutyric acid+Cysteine


α-Ketobutyric acid





4-Hydroxyphenylpyruvic acid Homogentisic acid 4-Maleylacetoacetic acid


see urea cycle



sulfinic acid

v t e

metabolic intermediates


Anabolism (tyrosine→epinephrine)

→ Levodopa → Dopamine
→ Epinephrine

Catabolism/ metabolites


DOPAL DOPAC MOPET Hydroxytyrosol 3-Methoxytyramine Homovanillic acid


3,4-Dihydroxymandelic acid Normetanephrine Vanillylmandelic acid 3-Methoxy-4-hydroxyphenylglycol Dihydroxyphenylethylene glycol







5-Hydroxyindoleacetic acid



v t e

receptor modulators



Agonists: 8-OH-DPAT Adatanserin Amphetamine Antidepressants (e.g., etoperidone, hydroxynefazodone, nefazodone, trazodone, triazoledione, vilazodone, vortioxetine) Atypical antipsychotics (e.g., aripiprazole, asenapine, brexpiprazole, cariprazine, clozapine, lurasidone, quetiapine, ziprasidone) Azapirones (e.g., buspirone, eptapirone, gepirone, perospirone, tandospirone) Bay R 1531 Befiradol BMY-14802 Cannabidiol Dimemebfe Dopamine Ebalzotan Eltoprazine Enciprazine Ergolines (e.g., bromocriptine, cabergoline, dihydroergotamine, ergotamine, lisuride, LSD, methylergometrine (methylergonovine), methysergide, pergolide) F-11461 F-12826 F-13714 F-14679 F-15063 F-15599 Flesinoxan Flibanserin Flumexadol Lesopitron LY-293284 LY-301317 mCPP MKC-242 Naluzotan NBUMP Osemozotan Oxaflozane Pardoprunox Piclozotan Rauwolscine Repinotan Roxindole RU-24969 S-14506 S-14671 S-15535 Sarizotan Serotonin
(5-HT) SSR-181507 Sunepitron Tryptamines (e.g., 5-CT, 5-MeO-DMT, 5-MT, bufotenin, DMT, indorenate, N-Me-5-HT, psilocin, psilocybin) TGBA01AD U-92016A Urapidil Vilazodone Xaliproden Yohimbine

Antagonists: Atypical antipsychotics (e.g., iloperidone, risperidone, sertindole) AV965 Beta blockers (e.g., alprenolol, carteolol, cyanopindolol, iodocyanopindolol, isamoltane, oxprenolol, penbutolol, pindobind, pindolol, propranolol, tertatolol) BMY-7378 CSP-2503 Dotarizine Ergolines (e.g., metergoline) Flopropione GR-46611 Isamoltane Lecozotan Mefway Metitepine
(methiothepin) MIN-117
(WF-516) MPPF NAN-190 Robalzotan S-15535 SB-649915 SDZ 216-525 Spiperone Spiramide Spiroxatrine UH-301 WAY-100135 WAY-100635 Xylamidine

Unknown/unsorted: Acetryptine Ergolines (e.g., ergometrine (ergonovine))


Agonists: CGS-12066A CP-93129 CP-94253 CP-122,288 CP-135807 Eltoprazine Ergolines (e.g., bromocriptine, dihydroergotamine, ergotamine, methylergometrine (methylergonovine), methysergide, pergolide) mCPP RU-24969 Serotonin
(5-HT) Triptans (e.g., avitriptan, donitriptan, eletriptan, sumatriptan, zolmitriptan) TFMPP Tryptamines (e.g., 5-BT, 5-CT, 5-MT, DMT) Vortioxetine

Antagonists: AR-A000002 Beta blockers (e.g., alprenolol, carteolol, isamoltane, oxprenolol, penbutolol, propranolol, tertatolol) Elzasonan Ergolines (e.g., metergoline) GR-127935 Isamoltane LY-393558 Metitepine
(methiothepin) SB-216641 SB-224289 SB-236057 Yohimbine

Unknown/unsorted: Ergolines (e.g., cabergoline, ergometrine (ergonovine), lisuride)


Agonists: CP-122,288 CP-135807 CP-286601 Ergolines (e.g., bromocriptine, cabergoline, dihydroergotamine, ergotamine, LSD, methysergide) GR-46611 L-694247 L-772405 mCPP PNU-109291 PNU-142633 Serotonin
(5-HT) TGBA01AD Triptans (e.g., almotriptan, avitriptan, donitriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, sumatriptan, zolmitriptan) Tryptamines (e.g., 5-BT, 5-CT, 5-Et-DMT, 5-MT, 5-(nonyloxy)tryptamine, DMT)

Antagonists: Alniditan BRL-15572 Elzasonan Ergolines (e.g., metergoline) GR-127935 Ketanserin LY-310762 LY-367642 LY-393558 LY-456219 LY-456220 Metitepine
(methiothepin) Mianserin Ritanserin Yohimbine Ziprasidone

Unknown/unsorted: Acetryptine Ergolines (e.g., lisuride, lysergol, pergolide)


Agonists: BRL-54443 Ergolines (e.g., methysergide) Serotonin
(5-HT) Triptans (e.g., eletriptan) Tryptamines (e.g., tryptamine)

Antagonists: Metitepine

Unknown/unsorted: Ergolines (e.g., ergometrine (ergonovine), lysergol, methylergometrine (methylergonovine)


Agonists: BRL-54443 CP-122,288 Ergolines (e.g., bromocriptine, lysergol, methylergometrine (methylergonovine) methysergide) Lasmiditan LY-334370 Serotonin
(5-HT) Triptans (e.g., eletriptan, naratriptan, sumatriptan) Tryptamines (e.g., 5-MT)

Antagonists: Mianserin Metitepine



Agonists: 25H/NB series (e.g., 25I-NBF, 25I-NBMD, 25I-NBOH, 25I-NBOMe, 25B-NBOMe, 25C-NBOMe, 25TFM-NBOMe, 2CBCB-NBOMe, 25CN-NBOH, 2CBFly-NBOMe) 2Cs (e.g., 2C-B, 2C-E, 2C-I, 2C-T-2, 2C-T-7, 2C-T-21) 2C-B-FLY 2CB-Ind 5-Methoxytryptamines (5-MeO-DET, 5-MeO-DiPT, 5-MeO-DMT, 5-MeO-DPT, 5-MT) α-Alkyltryptamines (e.g., 5-Cl-αMT, 5-Fl-αMT, 5-MeO-αET, 5-MeO-αMT, α-Me-5-HT, αET, αMT) AL-34662 AL-37350A Bromo-DragonFLY Dimemebfe DMBMPP DOx
(e.g., DOB, DOC, DOI, DOM) Efavirenz Ergolines (e.g., 1P-LSD, ALD-52, bromocriptine, cabergoline, ergine (LSA), ergometrine (ergonovine), ergotamine, lisuride, LA-SS-Az, LSB, LSD, LSD-Pip, LSH, LSP, methylergometrine (methylergonovine), pergolide) Flumexadol Jimscaline Lorcaserin MDxx (e.g., MDA (tenamfetamine), MDMA
(midomafetamine), MDOH, MMDA) O-4310 Oxaflozane PHA-57378 PNU-22394 PNU-181731 RH-34 Phenethylamines (e.g., lophophine, mescaline) Piperazines (e.g., BZP, quipazine, TFMPP) Serotonin
(5-HT) TCB-2 TFMFly Tryptamines (e.g., 5-BT, 5-CT, bufotenin, DET, DiPT, DMT, DPT, psilocin, psilocybin, tryptamine)

Antagonists: 5-I-R91150 5-MeO-NBpBrT AC-90179 Adatanserin Altanserin Antihistamines (e.g., cyproheptadine, hydroxyzine, ketotifen, perlapine) AMDA Atypical antipsychotics (e.g., amperozide, aripiprazole, asenapine, blonanserin, brexpiprazole, carpipramine, clocapramine, clorotepine, clozapine, fluperlapine, gevotroline, iloperidone, lurasidone, melperone, mosapramine, ocaperidone, olanzapine, paliperidone, quetiapine, risperidone, sertindole, zicronapine, ziprasidone, zotepine) Cinanserin CSP-2503 Deramciclane Dotarizine Eplivanserin Ergolines (e.g., amesergide, LY-53857, LY-215840, mesulergine, metergoline, methysergide, sergolexole) Fananserin Flibanserin Glemanserin Irindalone Ketanserin KML-010 Landipirdine LY-393558 mCPP Medifoxamine Metitepine
(methiothepin) MIN-101 MIN-117
(WF-516) Naftidrofuryl Nantenine Nelotanserin Opiranserin (VVZ-149) Pelanserin Phenoxybenzamine Pimavanserin Pirenperone Pizotifen Pruvanserin Rauwolscine Ritanserin S-14671 Sarpogrelate Serotonin
antagonists and reuptake inhibitors (e.g., etoperidone, hydroxynefazodone, lubazodone, mepiprazole, nefazodone, triazoledione, trazodone) SR-46349B TGBA01AD Teniloxazine Temanogrel Tetracyclic antidepressants (e.g., amoxapine, aptazapine, esmirtazapine, maprotiline, mianserin, mirtazapine) Tricyclic antidepressants (e.g., amitriptyline) Typical antipsychotics (e.g., chlorpromazine, fluphenazine, haloperidol, loxapine, perphenazine, pimozide, pipamperone, prochlorperazine, setoperone, spiperone, spiramide, thioridazine, thiothixene, trifluoperazine) Volinanserin Xylamidine Yohimbine

Unknown/unsorted: Ergolines (e.g., dihydroergotamine, nicergoline)


Agonists: 4-Methylaminorex Aminorex Amphetamines (e.g., chlorphentermine, cloforex, dexfenfluramine, fenfluramine, levofenfluramine, norfenfluramine) BW-723C86 DOx
(e.g., DOB, DOC, DOI, DOM) Ergolines (e.g., cabergoline, dihydroergocryptine, dihydroergotamine, ergotamine, methylergometrine (methylergonovine), methysergide, pergolide) Lorcaserin MDxx (e.g., MDA (tenamfetamine), MDMA
(midomafetamine), MDOH, [MMDA (drug)

Antagonists: Agomelatine Atypical antipsychotics (e.g., amisulpride, aripiprazole, asenapine, brexpiprazole, cariprazine, clozapine, N-desalkylquetiapine (norquetiapine), N-desmethylclozapine
(norclozapine), olanzapine, pipamperone, quetiapine, risperidone, ziprasidone) Cyproheptadine EGIS-7625 Ergolines (e.g., amesergide, bromocriptine, lisuride, LY-53857, LY-272015, mesulergine) Ketanserin LY-393558 mCPP Metadoxine Metitepine
(methiothepin) Pirenperone Pizotifen Propranolol PRX-08066 Rauwolscine Ritanserin RS-127445 Sarpogrelate SB-200646 SB-204741 SB-206553 SB-215505 SB-221284 SB-228357 SDZ SER-082 Tegaserod Tetracyclic antidepressants (e.g., amoxapine, mianserin, mirtazapine) Trazodone Typical antipsychotics (e.g., chlorpromazine) TIK-301 Yohimbine

Unknown/unsorted: Ergolines (e.g., ergometrine (ergonovine))


Agonists: 2Cs (e.g., 2C-B, 2C-E, 2C-I, 2C-T-2, 2C-T-7, 2C-T-21) 5-Methoxytryptamines (5-MeO-DET, 5-MeO-DiPT, 5-MeO-DMT, 5-MeO-DPT, 5-MT) α-Alkyltryptamines (e.g., 5-Cl-αMT, 5-Fl-αMT, 5-MeO-αET, 5-MeO-αMT, α-Me-5-HT, αET, αMT) A-372159 AL-38022A Alstonine CP-809101 Dimemebfe DOx
(e.g., DOB, DOC, DOI, DOM) Ergolines (e.g., ALD-52, cabergoline, dihydroergotamine, ergine (LSA), ergotamine, lisuride, LA-SS-Az, LSB, LSD, LSD-Pip, LSH, LSP, pergolide) Flumexadol Lorcaserin MDxx (e.g., MDA (tenamfetamine), MDMA
(midomafetamine), MDOH, MMDA) MK-212 Org 12962 Org 37684 Oxaflozane PHA-57378 Phenethylamines (e.g., lophophine, mescaline) Piperazines (e.g., aripiprazole, BZP, mCPP, quipazine, TFMPP) PNU-22394 PNU-181731 Ro60-0175 Ro60-0213 Serotonin
(5-HT) Tryptamines (e.g., 5-BT, 5-CT, bufotenin, DET, DiPT, DMT, DPT, psilocin, psilocybin, tryptamine) Vabicaserin WAY-629 WAY-161503 YM-348

Antagonists: Adatanserin Agomelatine Atypical antipsychotics (e.g., asenapine, clorotepine, clozapine, fluperlapine, iloperidone, melperone, olanzapine, paliperidone, quetiapine, risperidone, sertindole, ziprasidone, zotepine) Captodiame CEPC Cinanserin Cyproheptadine Deramciclane Desmetramadol Dotarizine Eltoprazine Ergolines (e.g., amesergide, bromocriptine, LY-53857, LY-215840, mesulergine, metergoline, methysergide, sergolexole) Etoperidone Fluoxetine FR-260010 Irindalone Ketanserin Ketotifen Latrepirdine
(dimebolin) Medifoxamine Metitepine
(methiothepin) Nefazodone Pirenperone Pizotifen Propranolol Ritanserin RS-102221 S-14671 SB-200646 SB-206553 SB-221284 SB-228357 SB-242084 SB-243213 SDZ SER-082 Tedatioxetine Tetracyclic antidepressants (e.g., amoxapine, aptazapine, esmirtazapine, maprotiline, mianserin, mirtazapine) TIK-301 Tramadol Trazodone Tricyclic antidepressants (e.g., amitriptyline, nortriptyline) Typical antipsychotics (e.g., chlorpromazine, loxapine, pimozide, pipamperone, thioridazine) Xylamidine

Unknown/unsorted: Efavirenz Ergolines (e.g., ergometrine (ergonovine), methylergometrine (methylergonovine))



Agonists: Alcohols (e.g., butanol, ethanol (alcohol), trichloroethanol) m-CPBG Phenylbiguanide Piperazines (e.g., BZP, mCPP, quipazine) RS-56812 Serotonin
(5-HT) SR-57227 SR-57227A Tryptamines (e.g., 2-Me-5-HT, 5-CT, bufotenidine (5-HTQ)) Volatiles/gases (e.g., halothane, isoflurane, toluene, trichloroethane) YM-31636

Antagonists: Alosetron AS-8112 Atypical antipsychotics (e.g., clozapine, olanzapine, quetiapine) Azasetron Batanopride Bemesetron
(MDL-72222) Bupropion Cilansetron CSP-2503 Dazopride Dolasetron Galanolactone Granisetron Hydroxybupropion ICS-205930 Lerisetron Memantine Ondansetron Palonosetron Ramosetron Renzapride Ricasetron Tedatioxetine Tetracyclic antidepressants (e.g., amoxapine, mianserin, mirtazapine) Thujone Tropanserin Tropisetron Typical antipsychotics (e.g., loxapine) Volatiles/gases (e.g., nitrous oxide, sevoflurane, xenon) Vortioxetine Zacopride Zatosetron

Unknown/unsorted: LY-53857 Piperazines (e.g., naphthylpiperazine)


Agonists: 5-MT BIMU8 Capeserod Cinitapride Cisapride CJ-033466 Dazopride Metoclopramide Minesapride Mosapride Prucalopride PRX-03140 Renzapride RS-67333 RS-67506 Serotonin
(5-HT) Tegaserod Velusetrag Zacopride

Antagonists: GR-113808 GR-125487 L-Lysine Piboserod RS-39604 RS-67532 SB-203186 SB-204070


Agonists: Ergolines (e.g., 2-Br-LSD (BOL-148), ergotamine, LSD) Serotonin
(5-HT) Tryptamines (e.g., 5-CT) Valerenic Acid

Antagonists: Asenapine Latrepirdine
(dimebolin) Metitepine
(methiothepin) Ritanserin SB-699551

Unknown/unsorted: Ergolines (e.g., metergoline, methysergide) Piperazines (e.g., naphthylpiperazine)


Agonists: Ergolines (e.g., dihydroergocryptine, dihydroergotamine, ergotamine, lisuride, LSD, mesulergine, metergoline, methysergide) Serotonin
(5-HT) Tryptamines (e.g., 2-Me-5-HT, 5-BT, 5-CT, 5-MT, Bufotenin, E-6801, E-6837, EMD-386088, EMDT, LY-586713, N-Me-5-HT, tryptamine) WAY-181187 WAY-208466

Antagonists: ABT-354 Atypical antipsychotics (e.g., aripiprazole, asenapine, clorotepine, clozapine, fluperlapine, iloperidone, olanzapine, tiospirone) AVN-101 AVN-211 AVN-322 AVN-397 BGC20-760 BVT-5182 BVT-74316 Cerlapirdine EGIS-12233 GW-742457 Idalopirdine Ketanserin Landipirdine Latrepirdine
(dimebolin) Metitepine
(methiothepin) MS-245 PRX-07034 Ritanserin Ro 04-6790 Ro 63-0563 SB-258585 SB-271046 SB-357134 SB-399885 SB-742457 Tetracyclic antidepressants (e.g., amoxapine, mianserin) Tricyclic antidepressants (e.g., amitriptyline, clomipramine, doxepin, nortriptyline) Typical antipsychotics (e.g., chlorpromazine, loxapine)

Unknown/unsorted: Ergolines (e.g., 2-Br-LSD (BOL-148), bromocriptine, lergotrile, pergolide) Piperazines (e.g., naphthylpiperazine)


Agonists: 8-OH-DPAT AS-19 Bifeprunox E-55888 Ergolines (e.g., LSD) LP-12 LP-44 RU-24969 Sarizotan Serotonin
(5-HT) Triptans (e.g., frovatriptan) Tryptamines (e.g., 5-CT, 5-MT, bufotenin, N-Me-5-HT)

Antagonists: Atypical antipsychotics (e.g., amisulpride, aripiprazole, asenapine, brexpiprazole, clorotepine, clozapine, fluperlapine, olanzapine, risperidone, sertindole, tiospirone, ziprasidone, zotepine) Butaclamol DR-4485 EGIS-12233 Ergolines (e.g., 2-Br-LSD (BOL-148), amesergide, bromocriptine, cabergoline, dihydroergotamine, ergotamine, LY-53857, LY-215840, mesulergine, metergoline, methysergide, sergolexole) JNJ-18038683 Ketanserin LY-215840 Metitepine
(methiothepin) Ritanserin SB-258719 SB-258741 SB-269970 SB-656104 SB-656104A SB-691673 SLV-313 SLV-314 Spiperone SSR-181507 Tetracyclic antidepressants (e.g., amoxapine, maprotiline, mianserin, mirtazapine) Tricyclic antidepressants (e.g., amitriptyline, clomipramine, imipramine) Typical antipsychotics (e.g., acetophenazine, chlorpromazine, chlorprothixene, fluphenazine, loxapine, pimozide) Vortioxetine

Unknown/unsorted: Ergolines (e.g., lisuride, pergolide) Piperazines (e.g., naphthylpiperazine)

See also: Receptor/signaling modulators Adrenergics Dopaminergics Melatonergics Monoamine reuptake inhibitors and releasing agents Monoamine metabolism modulators Monoamine neurotoxins

v t e


1-Methylpsilocin 2-Methyl-5-HT 4,5-DHP-DMT 4,5-MDO-DMT 4,5-MDO-DiPT 4-AcO-DALT 4-AcO-DET 4-AcO-DMT 4-AcO-DiPT 4-AcO-NMT 4-AcO-MET 4-AcO-DPT 4-AcO-MiPT 4-HO-DALT 4-HO-DET 4-HO-DiPT 4-HO-DSBT 4-HO-MET 4-HO-MiPT 4-HO-NMT 4-HO-αMT 4-Me-αET 4-Me-αMT 4-MeO-DiPT 4-MeO-DMT 5-BT 5-Bromo-DMT 5-CT 5-Chloro-αMT 5-Ethoxy-αMT 5-Fluoro-αMT 5-HO-αMT 5-HO-DiPT 5-HTP 5-Ethoxy-DMT 5-Ethyl-DMT 5-Fluoro-DMT 5-Methyl-DMT 5-Methoxytryptamine 5-MeO-7,N,N-TMT 5-Methyl-αET 5-MeO-αET 5-MeO-αMT 5-MeO-DALT 5-MeO-DET 5-MeO-DiPT 5-MeO-DMT 5-MeO-DPT 5-MeO-EiPT 5-MeO-EPT 5-MeO-MALT 5-MeO-MiPT 5-MeO-NBpBrT 5,7-Dihydroxytryptamine 5-(Nonyloxy)tryptamine 6-Fluoro-αMT 6-Hydroxymelatonin 7-Methyl-αET 7-Methyl-DMT Acetryptine Aeruginascin αET AL-37350A αMT BW-723C86 Baeocystin Bufotenidine Bufotenin
(5-HO-DMT) Convolutindole A DALT Desformylflustrabromine DET DiPT DMT DPT Ethocybin EiPT EMDT EPT FGIN-127 FGIN-143 HIOC Ibogaine Indorenate Iprocin Lespedamine Luzindole MET MiPT MPT Miprocin Melatonin MS-245 NAS N-Feruloylserotonin NMT Norbaeocystin Normelatonin O-4310 Oxypertine Plakohypaphorine PiPT Psilocin
(4-HO-DMT) Psilocybin
(4-PO-DMT) Rizatriptan Serotonin ST-1936 Sumatriptan Tryptamine Tryptophan Yohimbine Yuremamine Zolmitriptan

Authority control