5-Hydroxy-L-tryptophan

L-tryptophan by hydroxylation to 5-hydroxy-L-tryptophan by the enzyme, ttyptophan-5-hydroxylase. 5-Hydroxy-L-tryptophan is then rapidly decarboxylated by aromatic-L-amino acid deacarboxylase to 5-HT. The actions of 5-HT as a neurottansmitter ate terminated by neuronal reuptake and metabobsm. 

From L-tryptophan, the serotonin synthesis pathway also begins. Serotonin is 5-hydroxytryptamine. It is derived from L-tryptophan, which at first is simply hydroxylated to 5-hydroxy-L-tryptophan, and subsequently to the serotonin (Figure 39). Structurally, serotonin is also a 5-HT monoamine neurotransmitter. 

The a for structural development of serotonin (simple indole alkaloid) is L-tryptophan, and the j3 is 5-hydroxy-L-tryptophan (Figure 64). Serotonin is a monoamine. It is a hioactive alkaloid known as a neurotransmitter. It has been found in the cardiovascular system, in Wood cells and the peripheral and CNS. 

Hydroxy-L-tryptophan [4350-09-8] M 220.2, m 273 (dec), [a] -32.5 , [a] 5 -73.5 (c 1, H2O). Likely impurities are 5-hydroxy-D-tryptophan and 5-benzyloxytryptophan. Crystd under nitrogen from water by adding EtOH. Stored under nitrogen. 

Hydroxy-L-tryptophan Oxytriptanum) l3sC antidepressant (psysiological... 

Quality Control and 5-HTP (5-Hydroxy-L-tryptophan) Analysis of Griffonia Griffonia simplicifolia (DC.) Baill.) Seed Aeeessions Colleeted in Ghana... 

Table II. Content of 5-hydroxy-L-tryptophan in Seeds of Griffonia...

H2O), pKEst(i) 2.4, pKEst(2) 9.0, pKEst(3) 9.4, pKEst(4) 16 (NH). Likely impurities are 5-hydroxy-D-tryptophan and 5-benzyloxytryptophan. Crystallise 5-hydroxy-L-tryptophan under nitrogen from water by adding EtOH. Store it under nitrogen. Also dissolve it in the minimum volume of hot H2O ( 0.7g in 4mL) under nitrogen (charcoal) and allowed it to crystallise at 5°. The picrolonate crystalhses from H2O with m 184-186°(dec). [Greenstein Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 p 2732-2737 7967, Morris Armstrong J Org Chem 22 306 1957, Beilstein 22/14 V 278.]... 

Das YT, Bagchi M, Bagchi D, Preuss HG (2004) Safety of 5-hydroxy-L-tryptophan. Toxicol Lett, 150 111-122. 

The deadly contaminants compounds 1.12 and 1.13 were present at about 0.01%. The moral is to test products from new processes on animals first. Some samples of over-the-counter 5-hydroxy-L-tryptophan contained impurities that caused eosinophila-myalgia syndrome.56... 

DDC catalyzes the conversion of L-3,4-dihydroxyphenylalanine (l-DOPA) into dopamine (Figure 10), a neurotransmitter found in the nervous system and peripheral tissues of both vertebrates and invertebrates and also in plants where it is implicated in the biosynthesis of benzylisoquinoline alkaloids. " DDC also catalyzes the decarboxylation of tryptophan, phenylalanine, and tyrosine and of 5-hydroxy-L-tryptophan to give 5-hydroxytryptamine (serotonin), and, therefore, is also referred to as aromatic amino acid decarboxylase. Inhibitors of DDC, for example, carbiDOPA and benserazide, are currently used in the treatment of Parkinson s disease to increase the amount of l-DOPA in the brain. 

Figure 10 Synthesis of the neurotransmitters dopamine and serotonin through decarboxylation of the substrates l-DOPA and 5-hydroxy-L-tryptophan, respectively.

SYNTHESIS, STORAGE, AND RELEASE OF CATECHOLAMINES Synthesis—The steps in the synthesis of DA, NE (known outside the U.S. as noradrenaline), and Epi (known as adrenahne) are shown in Eigure 6-A. Tyrosine is sequentially 3-hydroxylated and decarboxylated to form DA. DA is 3-hydroxylated to yield NE (the transmitter in postganglionic nerves of the sympathetic branch of the ANS), which is N-methylated in chromaffin tissue to give Epi. The enzymes involved are not completely specific consequently, other endogenous substances and some drugs are also substrates. 5-hydroxytryptamine (5-HT, serotonin) can be produced from 5-hydroxy-L-tryptophan by aromatic L-amino acid decarboxylase (AAD or dopa decarboxylase). AAD also converts dopa into DA, and methyldopa to a-methyl-DA, which is converted to a-methyl-NE by dopamine /3-hydroxylase (Dj3H Table 6-4). 

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