tryptophan 5-hydroxylase 2; neuronal tryptophan hydroxylase; tryptophan 5-monooxygenase 2 (TPH2, NTPH)

Function

• serotonin biosynthesis, 1st step
• melatonin biosynthesis, 1st step

L-tryptophan + tetrahydrobiopterin + O2
        <-->
5-hydroxy-L-tryptophan + 4a-hydroxytetrahydrobiopterin

Cofactor: Fe+2

Kinetic parameters:

• KM=41.3 uM for L-tryptophan
• Vmax=833 nmol/min/mg enzyme

Structure

• belongs to the biopterin-dependent aromatic amino acid hydroxylase family
• contains 1 ACT domain

Alternative splicing

named isoforms=2

RNA editing

• modified positions = 433, 441, 468
• modulates kinetic properties of both isoforms

Expression

• brain specific

Pathology

• polymorphisms associated with bipolar disorder

More general terms

• hydroxylase; monooxygenase
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=121278
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:121278
• OMIM: https://mirror.omim.org/entry/607478
• OMIM: https://mirror.omim.org/entry/608516
• OMIM: https://mirror.omim.org/entry/613003
• UniProt: http://www.uniprot.org/uniprot/Q8IWU9.html