Aromatic L-amino acid decarboxylase: Difference between revisions

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'''Aromatic L-amino acid decarboxylase''' (AADC) is an [[enzyme]] that plays a crucial role in the [[biochemical]] processes of the human body. It is responsible for the decarboxylation of aromatic L-amino acids, which are essential for the synthesis of several important [[neurotransmitters]] and [[hormones]].
== Aromatic L-amino acid decarboxylase ==
 
[[File:DOPA_decarboxylase_dimer_1JS3.png|DOPA decarboxylase dimer structure|thumb|right]]
 
'''Aromatic L-amino acid decarboxylase''' (AADC), also known as '''DOPA decarboxylase''', is an enzyme that catalyzes the decarboxylation of aromatic L-amino acids to produce their corresponding amines. This enzyme plays a crucial role in the biosynthesis of several important neurotransmitters, including [[dopamine]], [[serotonin]], and [[histamine]].
 
== Structure ==
 
Aromatic L-amino acid decarboxylase is a homodimeric enzyme, meaning it consists of two identical subunits. Each subunit contains a [[pyridoxal phosphate]] (PLP) cofactor, which is essential for the enzyme's catalytic activity. The enzyme's structure has been elucidated through [[X-ray crystallography]], revealing details about its active site and the binding of substrates and cofactors.
 
[[File:3rbf.jpg|Crystal structure of aromatic L-amino acid decarboxylase|thumb|left]]


== Function ==
== Function ==


AADC is involved in the synthesis of several key neurotransmitters and hormones. It catalyzes the decarboxylation of aromatic L-amino acids, specifically [[L-DOPA]] to [[dopamine]], [[5-HTP]] to [[serotonin]], and [[L-tryptophan]] to [[tryptamine]]. These neurotransmitters and hormones play vital roles in various physiological functions, including mood regulation, motor control, and the body's response to stress.
AADC is responsible for the decarboxylation of L-DOPA to dopamine, 5-hydroxytryptophan to serotonin, and histidine to histamine. These reactions are critical steps in the biosynthetic pathways of these neurotransmitters, which are vital for normal neurological function.
 
== Mechanism ==
 
The enzyme operates through a mechanism involving the formation of a Schiff base between the PLP cofactor and the substrate. This intermediate facilitates the removal of the carboxyl group from the substrate, resulting in the formation of the corresponding amine.
 
[[File:AADC_mechanism.png|Mechanism of action of aromatic L-amino acid decarboxylase|thumb|right]]
 
== Clinical Significance ==


== Structure ==
Deficiencies in AADC activity can lead to a rare genetic disorder known as AADC deficiency, characterized by a lack of dopamine and serotonin production. This condition results in severe developmental and neurological symptoms, including movement disorders and autonomic dysfunction.
 
== Pathways ==


The AADC enzyme is a [[dimer]] composed of two identical subunits. Each subunit contains a [[pyridoxal phosphate]] (PLP) molecule, which is essential for the enzyme's catalytic activity. The PLP molecule forms a [[Schiff base]] with a lysine residue in the enzyme, which is crucial for the decarboxylation reaction.
AADC is involved in several key metabolic pathways:


== Clinical significance ==
* '''Dopamine biosynthesis''': Converts L-DOPA to dopamine, a critical neurotransmitter in the central nervous system.
* '''Serotonin biosynthesis''': Converts 5-hydroxytryptophan to serotonin, which is involved in mood regulation and other functions.
* '''Histamine biosynthesis''': Converts histidine to histamine, which plays a role in immune response and gastric acid secretion.


Deficiency in AADC is a rare genetic disorder known as [[Aromatic L-amino acid decarboxylase deficiency]] (AADC deficiency). This condition is characterized by severe developmental delays, movement disorders, and autonomic dysfunction. It is caused by mutations in the [[DDC gene]], which encodes the AADC enzyme.
[[File:Serotonin_biosynthesis.svg|Pathway of serotonin biosynthesis|thumb|left]]


== See also ==
== Related Pages ==


* [[Decarboxylation]]
* [[Dopamine]]
* [[Serotonin]]
* [[Histamine]]
* [[Pyridoxal phosphate]]
* [[Neurotransmitter]]
* [[Neurotransmitter]]
* [[Aromatic L-amino acid decarboxylase deficiency]]


== References ==
== External Links ==


{{reflist}}
* [https://en.wikipedia.org/wiki/Aromatic_L-amino_acid_decarboxylase Aromatic L-amino acid decarboxylase on Wikipedia]


[[Category:Enzymes]]
[[Category:Enzymes]]
[[Category:Biochemistry]]
[[Category:Neurotransmitter biosynthesis]]
[[Category:Neurotransmitters]]
[[Category:Decarboxylases]]
[[Category:Genetic disorders]]
{{enzyme-stub}}
{{medicine-stub}}

Latest revision as of 18:51, 23 March 2025

Aromatic L-amino acid decarboxylase[edit]

DOPA decarboxylase dimer structure

Aromatic L-amino acid decarboxylase (AADC), also known as DOPA decarboxylase, is an enzyme that catalyzes the decarboxylation of aromatic L-amino acids to produce their corresponding amines. This enzyme plays a crucial role in the biosynthesis of several important neurotransmitters, including dopamine, serotonin, and histamine.

Structure[edit]

Aromatic L-amino acid decarboxylase is a homodimeric enzyme, meaning it consists of two identical subunits. Each subunit contains a pyridoxal phosphate (PLP) cofactor, which is essential for the enzyme's catalytic activity. The enzyme's structure has been elucidated through X-ray crystallography, revealing details about its active site and the binding of substrates and cofactors.

Crystal structure of aromatic L-amino acid decarboxylase

Function[edit]

AADC is responsible for the decarboxylation of L-DOPA to dopamine, 5-hydroxytryptophan to serotonin, and histidine to histamine. These reactions are critical steps in the biosynthetic pathways of these neurotransmitters, which are vital for normal neurological function.

Mechanism[edit]

The enzyme operates through a mechanism involving the formation of a Schiff base between the PLP cofactor and the substrate. This intermediate facilitates the removal of the carboxyl group from the substrate, resulting in the formation of the corresponding amine.

Mechanism of action of aromatic L-amino acid decarboxylase

Clinical Significance[edit]

Deficiencies in AADC activity can lead to a rare genetic disorder known as AADC deficiency, characterized by a lack of dopamine and serotonin production. This condition results in severe developmental and neurological symptoms, including movement disorders and autonomic dysfunction.

Pathways[edit]

AADC is involved in several key metabolic pathways:

  • Dopamine biosynthesis: Converts L-DOPA to dopamine, a critical neurotransmitter in the central nervous system.
  • Serotonin biosynthesis: Converts 5-hydroxytryptophan to serotonin, which is involved in mood regulation and other functions.
  • Histamine biosynthesis: Converts histidine to histamine, which plays a role in immune response and gastric acid secretion.
Pathway of serotonin biosynthesis

Related Pages[edit]

External Links[edit]