tyrosiinhüdroksülaasipuudulikkus

Tyrosiinihydrolaasi, also known as tyrosine hydroxylase (TH), is a crucial enzyme in the biosynthesis of catecholamines. It is the rate-limiting enzyme in this pathway, meaning its activity dictates the overall speed of the process. TH catalyzes the conversion of the amino acid L-tyrosine into L-DOPA (3,4-dihydroxyphenylalanine). This reaction involves the hydroxylation of the tyrosine molecule at the meta position of the aromatic ring.

The enzyme belongs to the family of monooxygenases and requires molecular oxygen, ferrous iron (Fe2+), and a reducing agent, typically tetrahydrobiopterin (BH4), as cofactors. The gene encoding tyrosiinihydrolaasi is located on chromosome 7 in humans and is subject to complex transcriptional and post-translational regulation. This regulation allows for fine-tuning of catecholamine production in response to physiological demands and environmental cues.

Tyrosiinihydrolaasi is predominantly expressed in sympathetic neurons and in the adrenal medulla, tissues responsible for producing neurotransmitters and hormones like dopamine, norepinephrine, and epinephrine. These catecholamines play vital roles in the central nervous system and the peripheral nervous system, mediating functions such as mood regulation, attention, motor control, stress response, and cardiovascular regulation. Dysregulation of TH activity has been implicated in various neurological and psychiatric disorders, including Parkinson's disease and depression.