Succinate semialdehyde dehydrogenase (IPR010102)

Short name: Succ_semiAld_DH

Overlapping homologous superfamilies

Family relationships



Succinate semialdehyde dehydrogenase (SSADH) is one of three enzymes constituting 4-aminobutyrate (GABA) degradation in both prokaryotes and eukaryotes, catalysing the (NAD(P)+)-dependent catabolism reaction of succinate semialdehyde to succinate for metabolism by the citric acid cycle. In Escherichia coli, SSADH is located in a unidirectionally transcribed gene cluster encoding enzymes for GABA degradation and is suggested to be co-transcribed with succinate semialdehyde transaminase from a common promoter upstream of SSADH [PMID: 8297211]. Similar gene arrangements can be found in characterised Ralstonia eutropha (Alcaligenes eutrophus) [PMID: 10564790] and the genome analysis of Bacillus subtilis.

Prokaryotic SSADH enzymes (EC: share high sequence homology to characterised SSADH from rat and human (EC:, exhibiting conservation of proposed cofactor binding residues, and putative active sites (G-237 and G-242, C-293 and G-259 respectively of rat SSADH) [PMID: 7814412].

Eukaryotic SSADH enzymes exclusively utilise NAD+ as a cofactor, exhibiting little to no NADP+ activity [PMID: 3888627]. While a NADP+ preference has been detected in prokaryotes in addition to both NADP+- and NAD+-dependencies as in E. coli, Pseudomonas, and Klebsiella pneumoniae [PMID: 10564790]. The function of this alternative SSADH currently is unknown, but has been suggested to play a possible role in 4-hydroxyphenylacetic degradation [PMID: 10564790].

SSADH enzyme belongs to the aldehyde dehydrogenase family, sharing a common evolutionary origin and enzymatic mechanism with lactaldehyde dehydrogenase [PMID: 1917845]. Like in lactaldehyde dehydrogenase and SSADH, the mammalian catalytic glutamic acid and cysteine residues are conserved in all the enzymes of this family.

GO terms

Biological Process

GO:0009450 gamma-aminobutyric acid catabolic process
GO:0055114 oxidation-reduction process

Molecular Function

GO:0009013 succinate-semialdehyde dehydrogenase [NAD(P)+] activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.