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Aromatic L-amino acid decarboxylase is active as a homodimer. Before addition of the pyridoxal phosphate cofactor, the apoenzyme exists in an open conformation. Upon cofactor binding, a large structural transformation occurs as the subunits pull closer and close the active site. This conformational change results in the active, closed ...
Aromatic L-amino acid decarboxylase deficiency has an autosomal recessive pattern of inheritance. Aromatic L-amino acid decarboxylase deficiency is an autosomal recessive condition, meaning an individual needs to have two faulty copies of the DDC gene in order to be affected. Usually, one copy is inherited from each parent. [3]
L-Tyrosine is converted into L-DOPA by the enzyme tyrosine hydroxylase, with tetrahydrobiopterin, O 2, and iron (Fe 2+) as cofactors. [25] L-DOPA is converted into dopamine by the enzyme aromatic L-amino acid decarboxylase (also known as DOPA decarboxylase), with pyridoxal phosphate as the cofactor. [25]
The enzyme dopamine hydroxylase requires copper as a cofactor (not shown in the diagram) and DOPA decarboxylase requires PLP (not shown in the diagram). The rate limiting step in catecholamine biosynthesis through the predominant metabolic pathway is the hydroxylation of L-tyrosine to L-DOPA. [citation needed]
l-DOPA is produced from the amino acid l-tyrosine by the enzyme tyrosine hydroxylase. l-DOPA can act as an l-tyrosine mimetic and be incorporated into proteins by mammalian cells in place of l-tyrosine, generating protease-resistant and aggregate-prone proteins in vitro and may contribute to neurotoxicity with chronic l-DOPA administration. [10]
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.
Dihydropteridine reductase deficiency (DHPRD) is a genetic disorder affecting the tetrahydrobiopterin (BH4) synthesis pathway, inherited in the autosomal recessive pattern. It is one of the six known disorders causing tetrahydrobiopterin deficiency , and occurs in patients with mutations of the QDPR gene.