| DOPA decarboxylase (aromatic L-amino acid decarboxylase) | |
|---|---|
| Symbol(s): | DDC |
| Locus: | 7 p11 |
| EC number | 4.1.1.28 |
| EntrezGene | 1644 |
| OMIM | 107930 |
| RefSeq | NM_000790 |
| UniProt | P20711 |
Aromatic L-amino acid decarboxylase (EC 4.1.1.28, synonyms: DOPA decarboxylase, tryptophan decarboxylase, 5-hydroxytryptophan decarboxylase, AAAD) is a lyase enzyme.
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 the rate-limiting enzyme in the formation of biogenic trace amines.
Genetics[]
The gene encoding the enzyme is located on chromosome 7 in humans.[1]
See also[]
- Aromatic amino acids
Reference[]
- ↑ 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.
External links[]
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Carbon-carbon lyases (EC 4.1) | |
|---|---|
| 4.1.1: Carboxy-lyases |
Pyruvate decarboxylase -Oxaloacetate decarboxylase - Acetoacetate decarboxylase - Malonyl-CoA decarboxylase - Glutamate decarboxylase - Ornithine decarboxylase - Lysine decarboxylase - Phosphoribosylaminoimidazole carboxylase - Histidine decarboxylase - Uridine monophosphate synthetase/Orotidine 5'-phosphate decarboxylase - Aromatic L-amino acid decarboxylase - Phosphoenolpyruvate carboxylase - Pyrophosphomevalonate decarboxylase - Uroporphyrinogen III decarboxylase - RuBisCO - Phosphoenolpyruvate carboxykinase - Adenosylmethionine decarboxylase |
| 4.1.2: Aldehyde-lyases |
Aldolase A/Aldolase B - 2-hydroxyphytanoyl-CoA lyase |
| 4.1.3: Oxo-acid-lyases |
3-hydroxy-3-methylglutaryl-CoA lyase |
Amino acid metabolism enzymes | |
|---|---|
| phenylalanine→tyrosine→fumarate→TCA |
Phenylalanine hydroxylase - Tyrosine aminotransferase - 4-Hydroxyphenylpyruvate dioxygenase - Homogentisate 1,2-dioxygenase - Fumarylacetoacetate hydrolase |
| tyrosine→dopamine→epinephrine |
Tyrosine hydroxylase - Aromatic L-amino acid decarboxylase - Dopamine beta hydroxylase - Phenylethanolamine N-methyltransferase |
| leucine→HMG-CoA (keto) |
Branched-chain alpha-keto acid dehydrogenase complex - Isovaleryl coenzyme A dehydrogenase - Methylcrotonyl-CoA carboxylase |
| isoleucine/valine→propionyl-CoA |
Branched-chain alpha-keto acid dehydrogenase complex |
| methionine→cysteine→propionyl-CoA |
Methionine adenosyltransferase - Adenosylhomocysteinase - (or MTR) - Cystathionine beta synthase - Cystathionine gamma-lyase |
| propionyl-CoA→succinyl-CoA→TCA |
Propionyl-CoA carboxylase - Methylmalonyl-CoA mutase |
| serine→glycine |
Serine hydroxymethyltransferase |
| histidine |
to histamine: Histidine decarboxylase - to glutamate: Histidine ammonia-lyase - Urocanate hydratase - Formiminotransferase cyclodeaminase |
| tryptophan→serotonin→melatonin |
Tryptophan hydroxylase - Aromatic L-amino acid decarboxylase - 5-hydroxyindole-O-methyltransferase |
| asparagine→aspartate→oxaloacetate→TCA |
Asparaginase/Asparagine synthetase - Aspartate transaminase |
| glutamate |
Glutaminase - Glutamate decarboxylase |
| lysine→keto |
Saccharopine dehydrogenase |
| other | |
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