Succinic semialdehyde

Succinic semialdehyde (SSA) is a GABA and GHB metabolite. It is formed from GABA by the action of GABA transaminase (4-aminobutyrate aminotransferase) and further oxidised to become succinic acid, which enters TCA cycle. SSA is oxidized into succinic acid by the enzyme succinic semialdehyde dehydrogenase, which uses NAD⁺ as a cofactor.^[2][3]  When the oxidation of succinic semialdehyde to succinic acid is impaired, accumulation of succinic semialdehyde takes place which leads to succinic semialdehyde dehydrogenase deficiency.^[3]

Quick facts Names, Identifiers ...

Succinic semialdehyde

Names
Preferred IUPAC name 4-Oxobutanoic acid
Identifiers
CAS Number	692-29-5 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16265 Y
ChemSpider	1080 Y
ECHA InfoCard	100.155.728
KEGG	C00232 Y
MeSH	Succinic+semialdehyde
PubChem CID	1112
UNII	M73BX3CPMU Y
CompTox Dashboard (EPA)	DTXSID00219231
InChI InChI=1S/C4H6O3/c5-3-1-2-4(6)7/h3H,1-2H2,(H,6,7) Y Key: UIUJIQZEACWQSV-UHFFFAOYSA-N Y InChI=1/C4H6O3/c5-3-1-2-4(6)7/h3H,1-2H2,(H,6,7) Key: UIUJIQZEACWQSV-UHFFFAOYAS
SMILES O=CCCC(=O)O
Properties
Chemical formula	C4H6O3
Molar mass	102.089 g/mol
Appearance	oil
Boiling point	135 °C (275 °F; 408 K) at 14 mmHg
Solubility in water	soluble in water, ethanol, benzene, diethyl ether[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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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).^[4][5][6][7]