| DOPA decarboxylase (aromatic L-amino acid decarboxylase) | |
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| Ribbon diagram of a domestic pig DOPA decarboxylase dimer. From PDB 1JS3. | |
| Identifiers | |
| Symbol | DDC |
| Entrez | 1644 |
| HUGO | 2719 |
| OMIM | 107930 |
| RefSeq | NM_000790 |
| UniProt | P20711 |
| Other data | |
| EC number | 4.1.1.28 |
| Locus | Chr. 7 p11 |
Aromatic L-amino acid decarboxylase (EC 4.1.1.28, synonyms: DOPA decarboxylase, tryptophan decarboxylase, 5-hydroxytryptophan decarboxylase, AAAD) is a lyase enzyme.
Contents |
Reactions
It catalyzes several different decarboxylation reactions:
- L-DOPA to dopamine - a neurotransmitter
- 5-HTP to serotonin (5-HT) - also a neurotransmitter
- tryptophan to tryptamine - a precursor to many alkaloids found in plants and animals
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.
Genetics
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
References
- ^ 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:. PMID 1612608.
- ^ 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:. PMID 10578236.
- ^ 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:. PMID 11992572.
External links
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