Dopa decarboxylase is a homodimeric, pyridoxal phosphate dependent enzyme. Dopa decarboxylase is involved in 2 metabolic pathways, synthesizing 2 significant neurotransmitters: dopamine and serotonin which both take part in numerous clinical disorders, including Parkinson's disease. Dopa decarboxylase is located in different areas of the brain and is mostly found in basal ganglia. Dopa decarboxylase catalyzes the decarboxylation of L-3,4-dihydroxyphenylalanine (DOPA) to dopamine, L-5-hydroxytryptophan to serotonin and L-tryptophan to tryptamine. Defects in Dopa decarboxylase leads to aromatic L-amino-acid decarboxylase deficiency (AADCD). AADCD deficiency is an inborn error in neurotransmitter metabolism that causes combined serotonin and catecholamine deficiency Synonyms: DDC, AADC, Aromatic-L-amino-acid decarboxylase, DOPA decarboxylase