L-5-Hydroxytryptophan

Chemical Properties

white to pale grey powder

Uses

5-Hydroxy-L-Tryptophan is a hydroxylated metabolite of L-Tryptophan

Uses

A labelled metabolite of Tryptophan

Uses

5-Hydroxy-L-tryptophan has been used:

• to inject experimental mice for serotonin detection
• as a precursor of 5-hydroxytryptamine and injected in pregnant mice and neonatal rats for vital neutral red staining of lung slices
• as a standard in citrate-acetate buffer for its use in high performance liquid chromatography (HPLC) analysis

Definition

ChEBI: 5-hydroxy-L-tryptophan is the L-enantiomer of 5-hydroxytryptophan. It has a role as a human metabolite, a plant metabolite and a mouse metabolite. It is a 5-hydroxytryptophan, a hydroxy-L-tryptophan and a non-proteinogenic L-alpha-amino acid. It is an enantiomer of a 5-hydroxy-D-tryptophan. It is a tautomer of a 5-hydroxy-L-tryptophan zwitterion.

General Description

Colorless to pale pink crystals.

Air & Water Reactions

L-5-Hydroxytryptophan is sensitive to air. Slightly water soluble .

Reactivity Profile

L-5-Hydroxytryptophan reacts with bases. .

Fire Hazard

Flash point data for L-5-Hydroxytryptophan are not available, however, L-5-Hydroxytryptophan is probably combustible.

Trade name

Levothym (Promonta Lundbeck, Germany), Lévotonine (Panpharma, France), Oxyfan (Coli, Italy), Tript-OH (Sigma- Tai, Italy).

Biochem/physiol Actions

Hydroxylation of L-tryptophan occurs in the brain during serotonin synthesis. This is a step that controls the production of serotonin and also yields 5-hydroxy-l-tryptophan (5-HTP) as a metabolite. Thus, consumption 5-HTP, increases the serotonin level, which might result in depression, lack of sleep and severe headache.

Purification Methods

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 5o. The picrolonate crystallises from H2O with m 184-186o(dec). [Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 p 2732-2737 1961, Morris & Armstrong J Org Chem 22 306 1957, Beilstein 22/14 V 278.]