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Tyrosine hydroxylase deficiency; Simplified overview of the biosynthesis and catabolism of serotonin and the catecholamines, with tyrosine hydroxylase (TH) and its cofactor tetrahydrobiopterin (BH 4) circled in red. Note that different parts of these processes take place in different tissues.
Tyrosine hydroxylase or tyrosine 3-monooxygenase is the enzyme responsible for catalyzing the conversion of the amino acid L-tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA). [ 5 ] [ 6 ] It does so using molecular oxygen (O 2 ), as well as iron (Fe 2+ ) and tetrahydrobiopterin as cofactors .
Hawkinsinuria is an autosomal dominant metabolic disorder affecting the metabolism of tyrosine. [1] [2] Normally, the breakdown of the amino acid tyrosine involves the conversion of 4-hydroxyphenylpyruvate to homogentisate by 4-hydroxyphenylpyruvate dioxygenase. Complete deficiency of this enzyme would lead to tyrosinemia III. In rare cases ...
Tyrosine hydroxylase is the rate limiting enzyme responsible for the transformation of L-Tyrosine to L-3,4-dihydroxyphenylalanine , a catecholamine precursor. Catecholamines, dopamine , epinephrine , and norepinephrine , signal different stressors so the body can activate pathways to return towards homeostasis.
The enzyme tyrosine hydroxylase (TH) converts the amino acid L-tyrosine into 3,4-dihydroxyphenylalanine (L-DOPA). The hydroxylation of L -tyrosine by TH results in the formation of the DA precursor L -DOPA, which is metabolized by aromatic L -amino acid decarboxylase (AADC; see Cooper et al., 2002 [ citation needed ] ) to the transmitter dopamine.
Sometimes a lumbar puncture is performed to measure concentrations of biopterin and neopterin, which can help determine the exact form of dopamine-responsive movement disorder: early onset parkinsonism (reduced biopterin and normal neopterin), GTP cyclohydrolase I deficiency (both decreased) and tyrosine hydroxylase deficiency (both normal).
Phenylketonuria (PKU)-like symptoms, including more pronounced developmental defects, skin irritation, and vomiting, may appear when phenylalanine levels are near 20 mg/dL (1200 mol/L). [1] Hyperphenylalaninemia is a recessive hereditary metabolic disorder that is caused by the body's failure to convert phenylalanine to tyrosine as a result of ...
Tyramine (/ ˈ t aɪ r ə m iː n / TY-rə-meen) (also spelled tyramin), also known under several other names, [note 1] is a naturally occurring trace amine derived from the amino acid tyrosine. [4] Tyramine acts as a catecholamine releasing agent .