DL-Tryptophan

Cosmetic ingredients (Tryptophan) -> CIR (Cosmetic Ingredient Review)

Antistatic

log Kow = -1.06

-1.06

FLAT TASTE

Slightly bitter

Leaflets or plates from dilute alcohol

White to slightly yellowish-white ... crystals or crystalline powder

1 to 5 mg/mL at 68 °F (NTP, 1992)

Slightly soluble in acetic acid, ethanol; insoluble in ethyl ether

Solubility in water: 0.23 g/L at 0 °C, 11.4 g/L at 25 °C, 17.1 g/L at 50 °C, 27.95 g/L at 75 °C, 49.9 g/L at 100 °C

Soluble 1 in 100 of water; very slightly soluble in alcohol; practically insoluble chloroform and ether; soluble in hot alcohol and solutions of dilute acids and alkali hydroxides.

13.4 mg/mL at 25 °C

This chemical does not meet GHS hazard criteria for 98.7% (222 of 225) of all reports.

Not Classified

Aggregated GHS information provided per 225 reports by companies from 5 notifications to the ECHA C&L Inventory.

Chemical: Tryptophan

Chemical: L-Tryptophan

Regulation (EC) No 1831/2003 (amended)

Status: Active Update: 15-09-2022 https://echa.europa.eu/registration-dossier/-/registered-dossier/10835

Tryptophan: Does not have an individual approval but may be used under an appropriate group standard

l-Tryptophan: Does not have an individual approval but may be used under an appropriate group standard

IMAP assessments - DL-Tryptophan: Environment tier I assessment

IMAP assessments - L-Tryptophan: Environment tier I assessment

Teratogenic effects observed in experimental animals at high doses; [Shepard's Catalog of Teratogenic Agents] No evidence of carcinogenicity in rats or mice; [NTP] May cause irritation; The FDA and CDC have established a possible link between L-tryptophan and eosinophilia-myalgia syndrome; [Sigma-Aldrich MSDS]

L-Tryptophan is a food additive permitted for direct addition to food for human consumption, as long as 1) the quantity of the substance added to food does not exceed the amount reasonably required to accomplish its intended physical, nutritive, or other technical effect in food, and 2) any substance intended for use in or on food is of appropriate food grade and is prepared and handled as a food ingredient.

Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses. A number of active ingredients have been present in OTC drug products for various uses, as described below. However, based on evidence currently available, there are inadequate data to establish general recognition of the safety and effectiveness of these ingredients for the specified uses: tryptophan is included in weight control drug products.

NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C. (2009).[Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html]

DHEW/NCI; Bioassay of L-Tryptophan for Possible Carcinogenicity CAS No. 73-22-3 (NCI-CG-TR-71) (1978) Technical Report Series No. 71 DHEW Pub No. (NIH) 78-1321[Available from, as of March 29, 2010: http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/tr071.pdf]

Residues of tryptophan are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only. Use: synergist. Limit: maximum of 0.5% of formulation.

Acidic salts, such as L-TRYPTOPHAN, are generally soluble in water. The resulting solutions contain moderate concentrations of hydrogen ions and have pH's of less than 7.0. They react as acids to neutralize bases. These neutralizations generate heat, but less or far less than is generated by neutralization of inorganic acids, inorganic oxoacids, and carboxylic acid. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible. Many of these compounds catalyze organic reactions.

In late 1989 the first notification linking the eosinophilia-myalgia syndrome with the use of tryptophan-containing products was made in the USA. There followed a number of similar published case reports from the USA, Europe, and Japan. Reviews of tryptophan-associated eosinophilia-myalgia syndrome have noted that by early 1990 over 1500 cases were known in the USA. In early 1990 the CDC in the USA summarized the features and known reports concerning the syndrome. As the name implies the characteristic features are an intense eosinophilia together with disabling fatigue and muscle pain, although multisystem organ involvement and inflammatory disorders affecting the joints, skin, connective tissue, lungs, heart, and liver have also been recorded. Symptoms have generally developed over several weeks and the syndrome has occurred in patients who had been receiving tryptophan for many years previously with no untoward effect. In most patients slow and gradual improvement in the degree of eosinophilia and other clinical manifestations has followed the withdrawal of tryptophan, but in some patients the disease has progressed despite withdrawal and there have been fatalities. The inflammatory condition has necessitated the use of corticosteroids in some patients. The eosinophilia-myalgia syndrome has been reported in patients taking both tryptophan-containing prescription products for depression and non-prescription dietary supplements for a number of disorders including insomnia, the premenstrual syndrome, and stress; it does not appear to have occurred in patients receiving amino-acid preparations containing tryptophan as part of total parenteral nutrition regimens. The recognition of this syndrome led to the withdrawal of tryptophan-containing products or severe restrictions being imposed upon their use in many countries during 1990. Various theories were proposed as to the reason for the association of tryptophan with this syndrome. Confusion existed because the reports implicated a very wide range of products from different manufacturers. However, later evidence appeared to have confirmed that contaminated tryptophan had originated from a single manufacturer in Japan. Bulk tryptophan was imported from Japan for manufacture into finished pharmaceutical dosage forms and it was noted in one of these reports that a single product was often found to contain two or more lots of powdered tryptophan that were blended together during the production of tablets or capsules. Many trace contaminants have been found in batches of tryptophan associated with the syndrome. One contaminant has been identified as 1,1'-ethylidenebis(tryptophan). Its inclusion in bulk tryptophan powder appeared to coincide with alterations in the manufacturing conditions that involved a change in the strain of Bacillus amyloliquefaciens used in the fermentation process and a reduction in the amount of charcoal used for purification. Other investigations indicated the presence of bacitracin-like peptides in batches of the contaminated tryptophan. However, further work has provided only weak support for an association between the syndrome and any one particular contaminant and the causative agent remains to be confirmed. Nonetheless, since the syndrome only appeared to be associated with tryptophan from one manufacturer, tryptophan preparations were reintroduced in the UK in 1994 for restricted use under carefully monitored conditions. In January 2005, the UK requirement for patient registration and monitoring was removed.[Sweetman SC (ed), Martindale: The Complete Drug Reference.

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SMALL SPILLS AND LEAKAGE: If you spill this chemical, you should dampen the solid spill material with water, then transfer the dampened material to a suitable container. Use absorbent paper dampened with water to pick up any remaining material. Seal your contaminated clothing and the absorbent paper in a vapor-tight plastic bag for eventual disposal. Wash all contaminated surfaces with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

SRP: Criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

SRP: At the time of review, regulatory criteria for small quantity disposal are subject to significant revision, however, household quantities of waste pharmaceuticals may be managed as follows: Mix with wet cat litter or coffee grounds, double bag in plastic, discard in trash.

SRP: Expired or waste pharmaceuticals shall carefully take into consideration applicable DEA, EPA, and FDA regulations. It is not appropriate to dispose by flushing the pharmaceutical down the toilet or discarding to trash. If possible return the pharmaceutical to the manufacturer for proper disposal being careful to properly label and securely package the material. Alternatively, the waste pharmaceutical shall be labeled, securely packaged and transported by a state licensed medical waste contractor to dispose by burial in a licensed hazardous or toxic waste landfill or incinerator.

Residues of tryptophan are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only. Use: synergist. Limit: maximum of 5% of formulation.

RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter. (NTP, 1992)

Concentrations of tryptophan (free and protein bound) and its metabolites in plasma of maternal vein at delivery, umbilical vein, umbilical artery, neonatal vein and breast milk were determined by high performance liquid chromatography. The plasma levels of tryptophan and most of its metabolites in umbilical vein and artery were significantly higher than those in maternal vein. The concentration of total tryptophan in plasma of neonatal vein showed marked decrease at 24 h after birth in comparison with that at birth, but the total kynurenine concentration was not decreased in plasma of neonatal vein. The colostrum contained a high level of total tryptophan. There were high ratios of free to total tryptophan in colostrum, transitional and mature milk. In the blood, ratios of free to total of tryptophan and kynurenine were kept at constant level throughout the perinatal period.

Acetylsalicylic acid reduced serum-protein binding of tryptophan in man, causing rise in free serum tryptophan. Changes in metabolic pattern also occurred, with increased urinary excretion of xanthurenic acid and 3-hydroxylkynurenine and decreased excretion of 3-hydroxyanthranilic acid.

Although tryptophan has been given to patients receiving MAOIs in the belief that clinical efficacy may be improved, it should be noted that the adverse effects may also be potentiated.

Use of tryptophan with drugs that inhibit the reuptake of serotonin may exacerbate the adverse effects of the latter and precipitate the serotonin syndrome.

There have been occasional reports of sexual disinhibition in patients taking tryptophan with phenothiazines or benzodiazepines.

For more Interactions (Complete) data for (L)-Tryptophan (16 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 320(SRC), determined from a log Kow of -1.06(2) and a regression-derived equation(3), indicates that (L)-tryptophan is expected to have moderate mobility in soil(SRC). The pKa values of pKa1 2.38 (carboxylic acid) and pKa2 9.39 (primary amine)(4) indicate that this compound will exist as a zwitterion which may affect its adsorption to soils and sediments(SRC). Volatilization from moist soil is not expected because ions do not volatilize(SRC). Volatilization from moist soil is not expected because the acid/base exists as an anion/cation and anions/cations do not volatilize. (L)-Tryptophan is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.1X10-9 mm Hg at 25 °C(SRC), determined from a fragment constant method(5). Using the Warburg respirometer test, a theoretical BOD value of 4.6% in 24 hours(6) suggests that biodegradation is not expected to be an important environmental fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 320(SRC), determined from a log Kow of -1.06(2) and a regression-derived equation(3), indicates that (L)-tryptophan may adsorb to suspended solids and sediment(SRC). The pKa values of pKa1 2.38 (carboxylic acid) and pKa2 9.39 (primary amine)(4) indicate (L)-tryptophan will exist as a zwitterion at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process(5). According to a classification scheme(6), an estimated BCF of 3(SRC), from its log Kow(2) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Using the Warburg respirometer test, a theoretical BOD value of 4.6% in 24 hours(8) suggests that biodegradation is not expected to be an important environmental fate process in water(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), (L)-tryptophan, which has an estimated vapor pressure of 2.1X10-9 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase (L)-tryptophan may be removed from the air by wet or dry deposition(SRC). Photooxidation proceeds primarily by a singlet-oxygen mechanism(3). The oxidation products kynurenine and N-formylkynurenine accumulated most readily at pH 4-7.5 following irradiation of solutions of tryptophan containing riboflavin(4).

Concentrations of tryptophan (free and protein bound) and its metabolites in ... breast milk were determined by high performance liquid chromatography. ... The colostrum contained a high level of total tryptophan. There were high ratios of free to total tryptophan in colostrum, transitional and mature milk. ...

Safe in the present practices of use and concentration. Ingredient, concentration, and use information are available in documents discoverable at https://cir-reports.cir-safety.org

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⁺.

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.

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical.[Available from: http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=73-22-3]

The Koc of (L)-tryptophan is estimated as 320(SRC), using a log Kow of -1.06(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that (L)-tryptophan is expected to have moderate mobility in soil. The pKa values of pKa1 2.38 (carboxylic acid) and pKa2 9.39 (primary amine)(4) indicate that this compound will exist as a zwitterion which may affect its adsorption to soils and sediments(SRC).

(L)-Tryptophan is an essential amino acid for human development and a precursor of serotonin(1).

MILK & EGGS ... HAVE HIGH TRYPTOPHAN CONTENT.

/HUMAN EXPOSURE STUDIES/ Serotonin and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in human blood and brain cerebrospinal fluid (CSF) increase /were found/ after tryptophan loading, which is similar to the effects of L-tryptophan in animals. ... Elevations in blood and 5-HIAA and CSF serotonin after single doses of 3 or 6 g of L-tryptophan. However, ... a double-blind, placebo-controlled trial in six normal men fed 3 g/day of L-tryptophan in divided doses with meals for 3 days, found a 113% elevation in plasma tryptophan, but no changes in platelet or plasma serotonin or in plasma catecholamines. ... No changes in urinary catecholamines /were found/. Additionally, no changes in blood pressure, heart rate, plasma sodium levels or 24-hour sodium excretion in urine /were found/.

/HUMAN EXPOSURE STUDIES/ L-Tryptophan administration (2 g) as a single dose before a meal has been found to decrease subjective hunger ratings, food intake, and alertness in men, but not women.

/HUMAN EXPOSURE STUDIES/ 15 humans /were tested/ only once with 0, 1, 2, and 3 g of L-tryptophan. Individuals receiving 2 and 3 g of L-tryptophan had decreased hunger and alertness and increased faintness and dizziness. Administration of 1 g of L-tryptophan with 10 g of carbohydrates before each meal (3 g L-tryptophan/d) for 3 months did not affect body weight of obese humans.

/HUMAN EXPOSURE STUDIES/ Daily doses of 2.4 g of L-tryptophan for 2 weeks did not produce a significant reduction in the consumption of carbohydrate snacks in the majority of the 24 individuals.

For more Human Toxicity Excerpts (Complete) data for (L)-Tryptophan (19 total), please visit the HSDB record page.

L-Tryptophan is a food additive permitted for direct addition to food for human consumption, as long as 1) the quantity of the substance added to food does not exceed the amount reasonably required to accomplish its intended physical, nutritive, or other technical effect in food, and 2) any substance intended for use in or on food is of appropriate food grade and is prepared and handled as a food ingredient.

Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses. A number of active ingredients have been present in OTC drug products for various uses, as described below. However, based on evidence currently available, there are inadequate data to establish general recognition of the safety and effectiveness of these ingredients for the specified uses: tryptophan is included in weight control drug products.

Residues of tryptophan are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only. Use: synergist. Limit: maximum of 0.5% of formulation.

N - Nervous system

QN - Nervous system

... Skin is an optically inhomogeneous medium; reflection, refraction, scattering, and absorption all modify the radiation that reaches deeper structures. Important UV absorbers within the epidermis incl melanin, which varies greatly in content and location between individuals and races; urocanic acid, a deamination product of histidine found in sweat; and for shorter wavelengths, proteins containing tryptophan and tyrosine. The net optical effect is that shorter wavelengths are selectively absorbed in the superficial layers, although a biologically significant amt of UV-B reaches the dermis ... .

An essential amino acid for human development; precursor of serotonin.

...Tryptophan is a significant precursor of niacin for humans. It is for this reason that high corn diets result in clinical deficiency (pellagra) of niacin, corn being particularly deficient in tryptophan.

Corn and cereal grains contain fairly adequate quantities of niacin, but the vitamin is in a bound and unavailable form. They are also low in tryptophan. The combination of low tryptophan and unavailable dietary niacin results in a niacin deficiency. In current feeding practice in intensive agriculture situations, niacin or tryptophan should be added to high-concentrate diets of poultry and pigs.

For more Bionecessity (Complete) data for (L)-Tryptophan (30 total), please visit the HSDB record page.

Tryptophan is critical for the production of the body's proteins, enzymes and muscle tissue. It is also essential for the production of niacin, the synthesis of the neurotransmitter serotonin and melatonin. Tryptophan supplements can be used as natural relaxants to help relieve insomnia. Tryptophan can also reduce anxiety and depression and has been shown to reduce the intensity of migraine headaches. Other promising indications include the relief of chronic pain, reduction of impulsivity or mania and the treatment of obsessive or compulsive disorders. Tryptophan also appears to help the immune system and can reduce the risk of cardiac spasms. Tryptophan deficiencies may lead to coronary artery spasms. Tryptophan is used as an essential nutrient in infant formulas and intravenous feeding. Tryptophan is marketed as a prescription drug (Tryptan) for those who do not seem to respond well to conventional antidepressants. It may also be used to treat those afflicted with seasonal affective disorder (a winter-onset depression). Tryptopan serves as the precursor for the synthesis of serotonin (5-hydroxytryptamine, 5-HT) and melatonin (N-acetyl-5-methoxytryptamine).

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⁺.

Findings indicate that enhanced rates of serotonin turnover produced by (L)-tryptophan and physical restraint are associated with inhibition of thyroid-stimulating hormone (TSH) and stimulation of prolactin release from anterior pituitary in rats.

L-Tryptophan, an indispensable amino acid, serves as a precursor for several small molecules of functional significance including the vitamin niacin, the neurotransmitter serotonin, the metabolite tryptamine, and the pineal hormone melatonin. Increases in tryptophan have been shown to increase synthesis of the neurotransmitters in brain, blood, and other body organs.

Amino acids are selected for protein synthesis by binding with transfer RNA (tRNA) in the cell cytoplasm. The information on the amino acid sequence of each individual protein is contained in the sequence of nucleotides in the messenger RNA (mRNA) molecules, which are synthesized in the nucleus from regions of DNA by the process of transcription. The mRNA molecules then interact with various tRNA molecules attached to specific amino acids in the cytoplasm to synthesize the specific protein by linking together individual amino acids; this process, known as translation, is regulated by amino acids (e.g., leucine), and hormones. Which specific proteins are expressed in any particular cell and the relative rates at which the different cellular proteins are synthesized, are determined by the relative abundances of the different mRNAs and the availability of specific tRNA-amino acid combinations, and hence by the rate of transcription and the stability of the messages. From a nutritional and metabolic point of view, it is important to recognize that protein synthesis is a continuing process that takes place in most cells of the body. In a steady state, when neither net growth nor protein loss is occurring, protein synthesis is balanced by an equal amount of protein degradation. The major consequence of inadequate protein intakes, or diets low or lacking in specific indispensable amino acids relative to other amino acids (often termed limiting amino acids), is a shift in this balance so that rates of synthesis of some body proteins decrease while protein degradation continues, thus providing an endogenous source of those amino acids most in need. /Amino acids/

The mechanism of intracellular protein degradation, by which protein is hydrolyzed to free amino acids, is more complex and is not as well characterized at the mechanistic level as that of synthesis. A wide variety of different enzymes that are capable of splitting peptide bonds are present in cells. However, the bulk of cellular proteolysis seems to be shared between two multienzyme systems: the lysosomal and proteasomal systems. The lysosome is a membrane-enclosed vesicle inside the cell that contains a variety of proteolytic enzymes and operates mostly at acid pH. Volumes of the cytoplasm are engulfed (autophagy) and are then subjected to the action of the protease enzymes at high concentration. This system is thought to be relatively unselective in most cases, although it can also degrade specific intracellular proteins. The system is highly regulated by hormones such as insulin and glucocorticoids, and by amino acids. The second system is the ATP-dependent ubiquitin-proteasome system, which is present in the cytoplasm. The first step is to join molecules of ubiquitin, a basic 76-amino acid peptide, to lysine residues in the target protein. Several enzymes are involved in this process, which selectively targets proteins for degradation by a second component, the proteasome.

For more Mechanism of Action (Complete) data for (L)-Tryptophan (7 total), please visit the HSDB record page.

Hepatic.

In Hartnup disease ... tryptophane appear/s/ in urine due to defective renal and intestinal absorption of tryptophane ... It is an intermediary metabolite in the synthesis of serotonin (5-hydroxytryptamine) and 5-hydroxyindole acetic acid (HIAA).

Patients with bladder cancer excreted significantly more kynurenic acid, acetylkynurenine, kynurenine, and 3-hydroxykynurenine after ingesting a loading dose of L-tryptophan than did control subjects with no known disease.

Tryptophan is metabolized in the liver by tryptophan pyrrolase and tryptophan hydroxylase. Metabolites include hydroxytryptophan, which is then converted to serotonin, and kynurenine derivatives. Some tryptophan is converted to nicotinic acid and nicotinamide. Pyridoxine and ascorbic acid are cofactors in the decarboxylation and hydroxylation, respectively, of tryptophan; pyridoxine apparently prevents the accumulation of the kynurenine metabolites.

Yields indole-3-pyruvic acid in man ... and in rats; yields tryptamine in guinea pigs. /From table/

For more Metabolism/Metabolites (Complete) data for (L)-Tryptophan (21 total), please visit the HSDB record page.

(L)-Tryptophan with plant oils in soft gelatin capsules permitted lower dosage than with usual dosage form. Max of free tryptophan in serum was achieved in 1st hr whereas 4-5 times as much would be required with tablets or hard gelatin capsules.

Absorption and Fate. Tryptophan is readily absorbed from the gastro-intestinal tract. Tryptophan is extensively bound to serum albumin. It is metabolized to serotonin and other metabolites, incl kynurenine derivatives, and excreted in the urine. Pyridoxine and ascorbic acid appear to be concerned in its metabolism.

Although the free amino acids dissolved in the body fluids are only a very small proportion of the body's total mass of amino acids, they are very important for the nutritional and metabolic control of the body's proteins. ... Although the plasma compartment is most easily sampled, the concentration of most amino acids is higher in tissue intracellular pools. Typically, large neutral amino acids, such as leucine and phenylalanine, are essentially in equilibrium with the plasma. Others, notably glutamine, glutamic acid, and glycine, are 10- to 50-fold more concentrated in the intracellular pool. Dietary variations or pathological conditions can result in substantial changes in the concentrations of the individual free amino acids in both the plasma and tissue pools. /Amino acids/

After ingestion, proteins are denatured by the acid in the stomach, where they are also cleaved into smaller peptides by the enzyme pepsin, which is activated by the increase in stomach acidity that occurs on feeding. The proteins and peptides then pass into the small intestine, where the peptide bonds are hydrolyzed by a variety of enzymes. These bond-specific enzymes originate in the pancreas and include trypsin, chymotrypsins, elastase, and carboxypeptidases. The resultant mixture of free amino acids and small peptides is then transported into the mucosal cells by a number of carrier systems for specific amino acids and for di- and tri-peptides, each specific for a limited range of peptide substrates. After intracellular hydrolysis of the absorbed peptides, the free amino acids are then secreted into the portal blood by other specific carrier systems in the mucosal cell or are further metabolized within the cell itself. Absorbed amino acids pass into the liver, where a portion of the amino acids are taken up and used; the remainder pass through into the systemic circulation and are utilized by the peripheral tissues. /Amino acids/

For more Absorption, Distribution and Excretion (Complete) data for (L)-Tryptophan (9 total), please visit the HSDB record page.

CIR ingredient: Tryptophan

An essential amino acid; Used in biochemical research; [Merck Index] Used as a nutritional supplement for foods; [FDA] Used as a dietary supplement, for research, cereal enrichment, and as a medication; [HSDB] Permitted for use as an inert ingredient in non-food pesticide products; [EPA]

Nutrition and research; medicine; dietary supplement; cereal enrichment /Tryptophan/

Probe for studying protein structure and dynamics

Nutritional supplement (amino acid) in drugs and foods

BIOLOGICAL ACTIVITIES: Analgesic; Antidementia; Antidepressant; Antidyskinetic; Antihypertensive; Antiinsomniac; Antimanic; Antimenopausal; Antimigraine; Antioxidant; Antiparkinsonian; Antiphenylketonuric; Antiprostaglandin; Antipsychotic; Antirheumatic; Antiscolioticn;;Carcinogenic; Essential; Hypnotic; Hypoglycemic; Hypotensive; Insulinase-Inhibitor; Insulinotonic;Monoamine-Precursor; Prolactinogenic; Sedative; Serotoninergic; Tumor-Promoter /Tryptophan/

(1977) 2.34 X 10+7 g (Princpl Custms Dists)

(1979) 2.47 X 10+7 g (Princpl Custms Dists)

(1977) Not produced commercially in USA

(1979) Not produced commercially in USA

Production volumes for non-confidential chemicals reported under the Inventory Update Rule. [Table#4827]

Fermentation of natural or biologically available substances with Corynebacterium glutamicum; enzymatically from indole, pyruvic acid, and ammonia using microbial tryptophanase

Synthesis starting with beta-indolylaldehyde and hippuric acid; ... from hydantoin; alternate route starting with 3-indoleacetonitrile.

Grades: Reagent; Technical; Food Chemicals Codex /Tryptophan/

(L)-Tryptophan with plant oils in soft gelatin capsules.

Tryptophan: ACTIVE

L-Tryptophan: ACTIVE

An essential amino acid for human development; precursor of serotonin.

60 mg of tryptophan is approx equiv to 1.0 mg of niacin. /Tryptophan/

The amino acids that are incorporated into mammalian protein are alpha-amino acids, with the exception of proline, which is an alpha-imino acid. This means that they have a carboxyl group, an amino nitrogen group, and a side chain attached to a central alpha-carbon. Functional differences among the amino acids lie in the structure of their side chains. In addition to differences in size, these side groups carry different charges at physiological pH (e.g., nonpolar, uncharged but polar, negatively charged, positively charged); some groups are hydrophobic (e.g., branched chain and aromatic amino acids) and some hydrophilic (most others). These side chains have an important bearing on the ways in which the higher orders of protein structure are stabilized and are intimate parts of many other aspects of protein function.