What is tryptophan?

  • (noun): An amino acid that occurs in proteins; is essential for growth and normal metabolism; a precursor of niacin.
    Synonyms: tryptophane


Tryptophan (IUPAC-IUBMB abbreviation: Trp or W; IUPAC abbreviation: L-Trp or D-Trp; sold for medical use as Tryptan) is one of the 22 standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG. Only the L-stereoisomer of tryptophan is used in structural or enzyme proteins, but the D-stereoisomer is occasionally found in naturally produced peptides (for example, the marine venom peptide contryphan). The distinguishing structural characteristic of tryptophan is that it contains an indole functional group. It is an essential amino acid as demonstrated by its growth effects on rats.

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Some articles on tryptophan:

... The contryphans (conus + tryptophan) are a family of peptides that are active constituents of the poisonous venom produced by cone snail (genus conus) ... modification including epimerization of leucine and tryptophan, tryptophan bromination, amidation of the C-terminus, and proline hydroxylation ...
Tryptophan - Lifespan
... Rats fed a low tryptophan diet showed reduced blood levels of triiodothyronine, which was suggested to retard the aging process ... Rats on tryptophan-reduced diets have shown increased maximum life span and improved biomarkers of aging (although the rate of initial deaths was higher than in controls) ... Cancers upregulate the liver enzyme tryptophan dioxygenase because its primary product, kynurenine, increases tumor growth. ...
Selective Serotonin Reuptake Inhibitor - Mechanism of Action - SSRIs Versus 5-HT-Prodrugs - SSRIs Together With 5-HT-Prodrugs
... Biosynthetic serotonin is made from tryptophan, an amino acid ... In 1989, the Food and Drug Administration made tryptophan available by prescription only, in response to an outbreak of eosinophilia-myalgia syndrome caused by impure L ... With current standards, L-tryptophan is again available over the counter in the US as well as supplement 5-HTP, which is a direct precursor to serotonin ...
Corepressor - Function - Prokaryotes
... coli tryptophan repressor (TrpR) is only able to bind to DNA and repress transcription of the trp operon when its corepressor tryptophan is bound to it ... TrpR in the absence of tryptophan is known as an aporepressor and is inactive in repressing gene transcription ... Trp operon encodes enzymes responsible for the synthesis of tryptophan ...
Tryptophan Transaminase
... In enzymology, a tryptophan transaminase (EC is an enzyme that catalyzes the chemical reaction L-tryptophan + 2-oxoglutarate (indol-3-yl)pyruvate + L-glutamate Thus, the two substrates of this ... in common use include L-phenylalanine-2-oxoglutarate aminotransferase, tryptophan aminotransferase, 5-hydroxytryptophan-ketoglutaric transaminase, hydroxytryptophan aminotransferase, L-tryptophan aminotransferase, and L ... This enzyme participates in tryptophan metabolism ...