Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-4332
Thöny, B; Calvo, A C; Scherer, T; Svebak, R M; Haavik, J; Blau, N; Martinez, A (2008). Tetrahydrobiopterin shows chaperone activity for tyrosine hydroxylase. Journal of Neurochemistry, 106(2):672-681.
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Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of catecholamine neurotransmitters. Primary inherited defects in TH have been associated with l-DOPA responsive and non-responsive dystonia and infantile parkinsonism. In this study, we show that both the cofactor (6R)-l-erythro-5,6,7,8-tetrahydrobiopterin (BH(4)) and the feedback inhibitor and catecholamine product dopamine increase the kinetic stability of human TH isoform 1 in vitro. Activity measurements and synthesis of the enzyme by in vitro transcription-translation revealed a complex regulation by the cofactor including both enzyme inactivation and conformational stabilization. Oral BH(4) supplementation to mice increased TH activity and protein levels in brain extracts, while the Th-mRNA level was not affected. All together our results indicate that the molecular mechanisms for the stabilization are a primary folding-aid effect of BH(4) and a secondary effect by increased synthesis and binding of catecholamine ligands. Our results also establish that orally administered BH(4) crosses the blood-brain barrier and therapeutic regimes based on BH(4) supplementation should thus consider the effect on TH. Furthermore, BH(4) supplementation arises as a putative therapeutic agent in the treatment of brain disorders associated with TH misfolding, such as for the human TH isoform 1 mutation L205P.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > University Children's Hospital Zurich > Medical Clinic|
|DDC:||610 Medicine & health|
|Deposited On:||12 Nov 2008 18:00|
|Last Modified:||23 Nov 2012 17:24|
|Additional Information:||The definitive version is available at www.blackwell-synergy.com|
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