How DOPA Decarboxylase Affects Neurotransmitter Synthesis

DOPA decarboxylase (DDC) is responsible for catalyzing the conversion of aromatic amino acids into their corresponding amines during the synthesis of several important neurotransmitters. Specifically, DDC catalyzes the decarboxylation of L-DOPA to dopamine, L5-HTP to serotonin, L-histidine to histamine, phenylalanine to phenethylamine, L-tyrosine to tyramine, and tryptophan to tryptamine.

A number of mutations in the DDC gene can cause aromatic L-amino-acid decarboxylase deficiency (AADCD) (Gücüyener et al., 2014). AADCD is an inborn error in neurotransmitter metabolism that leads to combined serotonin and catecholamine deficiency. DDC's critical role in neurotransmitter synthesis makes it an important target in the study of Parkinson's disease, depression and other neuroscience related diseases.

Parkinson's patients experience motor system symptoms due to reduced levels of dopamine in the substantia nigra portion of the brain. The conversion of L-DOPA to dopamine by DDC is not typically a rate-limiting step of dopamine synthesis in healthy individuals, however it is a determining factor for patients with Parkinson's disease.

Although dopamine cannot cross the blood-brain barrier, treatment with exogenous L-DOPA can temporarily alleviate some symptoms as it is broken down by DDC in the brain. Unfortunately, up to 95% of the administered L-DOPA is metabolized by DDC in the blood prior to crossing the blood-brain barrier, causing adverse side effects including nausea, dyskinesias, and joint stiffness. However DDC inhibitors can be used to prevent premature L-DOPA metabolism in the blood, and thereby both increase efficacy and reduce side effects (Burkhard et al., 2001).

Bio-Techne offers a wide range of DDC research reagents for use in neuroscience research. For example, researchers used our Dopa Decarboxylase/DDC Antibody (NB300-174) to demonstrate the presence of neuronal and extraneuronal DCC at early developmental stages in the brain stem and the basal ganglia (Blechingberg et al., 2010). In another study, Bio-Techne's Dopa Decarboxylase/DDC Antibody (NBP1-56918) was used to demonstrate that DCC and VMAT2, which is necessary for packaging dopamine, were present in neurons within the A11 dopaminergic cell group (Koblinger et al., 2014). Finally, researchers used our DOPA Decarboxylase Antibody (NB100-1785) in a study on attention-deficit hyperactivity disorder (Voeller, 2004).