Aromatic L-amino acid decarboxylase

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dopa decarboxylase (aromatic L-amino acid decarboxylase)
Identifiers
Symbol(s)	DDC
Entrez	1644
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 an enzyme catalyzing the decarboxylation of L-DOPA or 5-HTP to yield the neurotransmitters dopamine and serotonin (5-HT), respectively. The enzyme uses pyridoxal phosphate as a cofactor. In normal dopamine and 5-HT neurotransmitter synthesis, AAAD is not the rate-limiting step of in either reaction. However, AAAD becomes the rate-limiting step of dopamine formation in Parkinson's Disease patients treated with L-DOPA.

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

The same enzyme is also able to the decarboxylate the amino acid tryptophan to tryptamine, a precursor to many alkaloids found in plants and animals.