Reaction: Tryptophan is hydroxylated
- in pathway: Serotonin and melatonin biosynthesis
The first and rate limiting step in serotonin (5-HT) biosynthesis is catalyzed by tryptophan hydroxylase. The enzyme requires iron(II), tetrahydrobiopterin, and dioxygen cofactors for the hydroxylation of L-tryptophan to 5-hydroxytryptophan. Tryptophan hydroxylase belongs to a small family of monooxygenases that utilize tetrahydrobiopterins. Other members are phenylalanine hydroxylase and tyrosine hydroxylase (Fitzpatrick, PF, 1999; Walther et al, 2003).
Reaction - small molecule participants:
4aOH-BH4 [cytosol]
5HTP [cytosol]
BH4 [cytosol]
L-Trp [cytosol]
O2 [cytosol]
Reactome.org reaction link: R-HSA-209828
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Reaction input - small molecules:
5,6,7,8-tetrahydrobiopterin
L-tryptophan zwitterion
dioxygen
Reaction output - small molecules:
4a-hydroxytetrahydrobiopterin
5-hydroxy-L-tryptophan zwitterion
Reactome.org link: R-HSA-209828