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Aromatic L-amino acid decarboxylase: Wikis


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DOPA decarboxylase (aromatic L-amino acid decarboxylase)
DOPA decarboxylase dimer 1JS3.png
Ribbon diagram of a domestic pig DOPA decarboxylase dimer. From PDB 1JS3.
Symbol DDC
Entrez 1644
HUGO 2719
OMIM 107930
RefSeq NM_000790
UniProt P20711
Other data
EC number
Locus Chr. 7 p11

Aromatic L-amino acid decarboxylase (EC, synonyms: DOPA decarboxylase, tryptophan decarboxylase, 5-hydroxytryptophan decarboxylase, AAAD) is a lyase enzyme.



It catalyzes several different decarboxylation reactions:

The enzyme uses pyridoxal phosphate as a cofactor.

As a rate-limiting step

In normal dopamine and serotonin (5-HT) neurotransmitter synthesis, AAAD is not the rate-limiting step in either reaction. However, AAAD becomes the rate-limiting step of dopamine synthesis in patients treated with L-DOPA (such as in Parkinson's Disease), and the rate-limiting step of serotonin synthesis in people treated with 5-HTP (such as in mild depression or dysthymia). AAAD is inhibited by Carbidopa outside of the blood brain barrier to inhibit the premature conversion of L-DOPA to Dopamine in the treatment of Parkinson's.

AAAD is the rate-limiting enzyme in the formation of biogenic trace amines.

dopamine   serotonin


The gene encoding the enzyme is referred to as DDC and located on chromosome 7 in humans.[1] Single nucleotide polymorphisms and other gene variations have been investigated in relation to neuropsychiatric disorders, e.g., a one-base pair deletion at –601 and a four-base pair deletion at 722–725 in exon 1 in relation to bipolar affective disorder[2] and autism.[3]

See also


  1. ^ Lisa J. Scherer, John D. McPherson, John J. Wasmuth and J. Lawrence Marsh (June 1992). "Human dopa decarboxylase: Localization to human chromosome 7p11 and characterization of hepatic cDNAs". Genomics 13 (2): 469–471. doi:10.1016/0888-7543(92)90275-W. PMID 1612608.  
  2. ^ A. D. Borglum, T. G. Bruun, T. E. Kjeldsen, H. Ewald, O. Mors, G. Kirov, C. Russ, B. Freeman, D. A. Collier & T. A. Kruse (November 1999). "Two novel variants in the DOPA decarboxylase gene: association with bipolar affective disorder". Molecular Psychiatry 4 (6): 545–541. doi:10.1038/ PMID 10578236.  
  3. ^ Marlene B. Lauritsen, Anders D. Borglum, Catalina Betancur, Anne Philippe, Torben A. Kruse, Marion Leboyer & Henrik Ewald (May 2002). "Investigation of two variants in the DOPA decarboxylase gene in patients with autism". American Journal of Medical Genetics 114 (4): 466–460. doi:10.1002/ajmg.10379. PMID 11992572.  

External links

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