Succinic semialdehyde (SSA) is a
GABA
GABA (gamma-aminobutyric acid, γ-aminobutyric acid) is the chief inhibitory neurotransmitter in the developmentally mature mammalian central nervous system. Its principal role is reducing neuronal excitability throughout the nervous system.
GA ...
and
GHB metabolite. It is formed from GABA by the action of
GABA transaminase
In enzymology, 4-aminobutyrate transaminase (), also called GABA transaminase or 4-aminobutyrate aminotransferase, or GABA-T, is an enzyme that catalysis, catalyzes the chemical reaction:
:4-aminobutanoate + 2-oxoglutarate \rightleftharpoons suc ...
(4-aminobutyrate aminotransferase) and further
oxidised
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...
to become
succinic acid
Succinic acid () is a dicarboxylic acid with the chemical formula (CH2)2(CO2H)2. In living organisms, succinic acid takes the form of an anion, succinate, which has multiple biological roles as a metabolic intermediate being converted into fum ...
, which enters
TCA cycle
The citric acid cycle—also known as the Krebs cycle, Szent–Györgyi–Krebs cycle, or TCA cycle (tricarboxylic acid cycle)—is a series of chemical reaction, biochemical reactions that release the energy stored in nutrients through acetyl-Co ...
. SSA is oxidized into succinic acid by the enzyme
succinic semialdehyde dehydrogenase, which uses
NAD+ as a
cofactor.
When the oxidation of succinic semialdehyde to succinic acid is impaired, accumulation of succinic semialdehyde takes place which leads to
succinic semialdehyde dehydrogenase deficiency
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare autosomal recessive disorder of the degradation pathway of the inhibitory neurotransmitter γ-aminobutyric acid, or GABA. The disorder has been identified in approximately 350 fami ...
.
In addition to the pathway involving GABA transaminase, gamma-hydroxybutyric acid (GHB) can also be metabolized to SSA via GHB dehydrogenase or by GHB transhydrogenase (D-2-hydroxyglutarate transhydrogenase).
See also
*
Transaminase
Transaminases or aminotransferases are enzymes that catalyze a transamination reaction between an amino acid and an α-keto acid. They are important in the synthesis of amino acids, which form proteins.
Function and mechanism
An amino acid con ...
(aminotransferase)
*
Succinic semialdehyde dehydrogenase deficiency
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare autosomal recessive disorder of the degradation pathway of the inhibitory neurotransmitter γ-aminobutyric acid, or GABA. The disorder has been identified in approximately 350 fami ...
References
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Aldehydes
Carboxylic acids
Gamma-Hydroxybutyric acid
Aldehydic acids