This domain is found in Tyrosine 3-monooxygenase from Rattus norvegicus (TH) and similar proteins from vertebrates. TH catalyses the hydroxylation of tyrosine to form 3,4-dihydroxyphenylalanine in the biosynthesis of the catecholamine neurotransmitters. This entry represents the regulatory domain, which is centrally located (C- terminal to Pfam:PF12549 and N-terminal to Pfam:PF00351). It is an ACT domain that shows a four stranded antiparallel beta-sheet and two alpha-helices connected by four loops. It adopts a dimeric configuration [1-3]. In humans, TH is associated with several disorders [4].

1: The solution structure of the regulatory domain of tyrosine hydroxylase. Zhang S, Huang T, Ilangovan U, Hinck AP, Fitzpatrick PF; J Mol Biol. 2014;426:1483-1497. PMID:24361276

2: Optimization of spirocyclic proline tryptophan hydroxylase-1 inhibitors. Goldberg DR, De Lombaert S, Aiello R, Bourassa P, Barucci N, Zhang Q, Paralkar V, Stein AJ, Holt M, Valentine J, Zavadoski W; Bioorg Med Chem Lett. 2017;27:413-419. PMID:28041831

3: Structural mechanism for tyrosine hydroxylase inhibition by dopamine and reactivation by Ser40 phosphorylation. Bueno-Carrasco MT, Cuellar J, Flydal MI, Santiago C, Krakenes TA, Kleppe R, Lopez-Blanco JR, Marcilla M, Teigen K, Alvira S, Chacon P, Martinez A, Valpuesta JM; Nat Commun. 2022;13:74. PMID:35013193

4: Recessively inherited L-DOPA-responsive dystonia caused by a point mutation (Q381K) in the tyrosine hydroxylase gene. Knappskog PM, Flatmark T, Mallet J, Ludecke B, Bartholome K; Hum Mol Genet. 1995;4:1209-1212. PMID:8528210