DDC

DOPA decarboxylase (DDC), also termed aromatic L-amino acid decarboxylase (AADC), catalyzes the biosynthesis of dopamine and serotonin through decarboxylation of L-DOPA and 5-HTP, respectively. This pyridoxal 5'-phosphate-dependent enzyme operates in both dopaminergic and serotonergic pathways, critically regulating neurotransmitter homeostasis. DDC dysfunction underlies AADC deficiency (OMIM #608643), a rare autosomal recessive disorder characterized by hypotonia, oculogyric crises, and autonomic dysfunction. In Parkinson's disease management, peripheral DDC inhibition by carbidopa enhances central L-DOPA bioavailability. Emerging therapies include adeno-associated virus-mediated DDC gene transfer (NCT02852213) and dopa-responsive dystonia-targeted pharmacochaperones. Recent structural studies resolving DDC's catalytic mechanism (PDB ID 7RZR) have informed small-molecule modulator development. DDC expression patterns in neuroendocrine tumors also make it a potential theranostic target for 18F-DOPA PET imaging and peptide receptor radionuclide therapy.