Tyrosine Hydroxylase (TH) is a rate limiting enzyme in the nervous system that converts L-tyrosine to L-3, 4-dihydroxyphenylalaine (L-DOPA) in the synthesis of catecholamines. The function of TH is tightly regulated and it is known that phosphorylation can regulate its activity. Dysregulation of pathways that modulate TH activity has been implicated in a number of neurodegenerative disorders such as Parkinson’s disease (PD). PD is a second most prevalent neurodegenerative disorder that is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta. How change in TH activity can contribute to PD is not completely known but previous studies have shown that oxidative and nitrosative stress can reduce TH activity in models of PD. In this study...[ Read more ]

Tyrosine Hydroxylase (TH) is a rate limiting enzyme in the nervous system that converts L-tyrosine to L-3, 4-dihydroxyphenylalaine (L-DOPA) in the synthesis of catecholamines. The function of TH is tightly regulated and it is known that phosphorylation can regulate its activity. Dysregulation of pathways that modulate TH activity has been implicated in a number of neurodegenerative disorders such as Parkinson’s disease (PD). PD is a second most prevalent neurodegenerative disorder that is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta. How change in TH activity can contribute to PD is not completely known but previous studies have shown that oxidative and nitrosative stress can reduce TH activity in models of PD. In this study, I find that apart from phosphorylation, TH can be modified by NO through S-nitrosylation, and this modification may affect TH activity. However there is still no evidence that this modification affects dopamine generation.