5-Hydroxytryptophan (5-HTP), also known as oxitriptan (INN), is a naturally occurring amino acid and chemical precursor as well as a metabolic intermediate in the biosynthesis of the neurotransmitters serotonin and melatonin from tryptophan. 5-HTP is sold over-the-counter in the United Kingdom, United States and Canada as a dietary supplement for use as an antidepressant, appetite suppressant, and sleep aid, and is also marketed in many European countries for the indication of major depression under trade names like Cincofarm, Levothym, Levotonine, Oxyfan, Telesol, Tript-OH, and Triptum. Several double-blind placebo-controlled clinical trials have demonstrated the effectiveness of 5-HTP in the treatment of depression, though a lack of high quality studies has been noted. More and larger studies are needed to determine if 5-HTP is truly effective in treating depression.
5-Hydroxytryptophan is decarboxylated to serotonin (5-hydroxytryptamine or 5-HT) by the enzyme aromatic-L-amino-acid decarboxylase with the help of vitamin B6. This reaction occurs both in nervous tissue and in the liver.
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This compound belongs to the class of organic compounds known as serotonins. These are compounds containing a serotonin moiety, which consists of an indole that bears an aminoethyl a position 2 and a hydroxyl group at position 5.
Catalyzes the formation of 5'adenyl-Trp and tRNA(Trp) but with 5-fold less activity than TrpRS. Increases the solubility of the nitric oxide synthase oxygenase (nos), as well as its affinity for substrate L-arginine and its nitric-oxide synthase activity. The complex between trpS2 and nos catalyzes the regioselective nitration of tryptophan at the 4-position.