GABA shunt (glutamate to GABA to succinate)

Three-step pathway, found in animals, plants and fungi, that converts L-glutamate to succinate through gamma-aminobutyrate (GABA) and succinate semialdehyde. It bypasses the 2-oxoglutarate-to-succinate segment of the TCA cycle. A pyridoxal-phosphate glutamate decarboxylase first converts L-glutamate to GABA and CO2 in the cytosol. A pyridoxal-phosphate GABA transaminase then transfers the amino group of GABA to an acceptor 2-oxo acid, giving succinate semialdehyde. Finally, succinate-semialdehyde dehydrogenase oxidizes succinate semialdehyde to succinate with NAD+ or NADP+. The chemistry is conserved, but the implementations differ between lineages. Animal glutamate decarboxylases form a family separate from the calmodulin-binding decarboxylases of plants and fungi. Animal and fungal GABA transaminases use 2-oxoglutarate and so regenerate glutamate, whereas the main plant enzyme uses pyruvate or glyoxylate. GABA catabolism takes place in the mitochondrial matrix of animals and plants but in the cytosol of budding yeast. In animals the shunt makes and clears the inhibitory neurotransmitter GABA. In plants it responds to stress and makes the GABA gradient that guides pollen tubes. In yeasts it lets GABA serve as a nitrogen source and helps cells tolerate oxidative stress. Organisms that lack glutamate decarboxylase, such as fission yeast, can still degrade GABA taken up from outside.

MODULE:gaba_shuntDRAFTCONCRETEMetabolic Pathwaymodules/gaba_shunt.yaml
GABA shuntGO:0006540
GO:0006540
GABA shunt
The module is grounded in the GO GABA shunt (GO:0006540): glutamate -> GABA -> succinate semialdehyde -> succinate.
GO:0009450
GABA catabolic process
Process term for the two catabolic steps (transamination and succinate-semialdehyde oxidation), which also act alone on imported GABA.
YeastPathways:GLUDEG-I-PWY-1
glutamate degradation I (S. cerevisiae, SGD YeastPathways)
YeastCyc lists GAD1 (glutamate decarboxylase), UGA1 (4-aminobutyrate aminotransferase) and UGA2 (succinate-semialdehyde dehydrogenase [NAD(P)+]). All three were retained.
YeastPathways:YEAST-4AMINOBUTMETAB-PWY
4-aminobutyrate degradation (S. cerevisiae, SGD YeastPathways)
YeastCyc lists UGA1 and UGA2 for GABA degradation; both reactions are the catabolic half of this module.
Reactome:R-HSA-888572
PXLP-K405-GAD1 decarboxylates L-Glu to form GABA
Reactions follow the human Reactome GABA-metabolism reactions R-HSA-888572 (GAD1), R-HSA-916855 (ABAT) and R-HSA-888548 (ALDH5A1).
file:human/GAD1/GAD1-ai-review.yaml
GAD1 gene review (human)
The glutamate-decarboxylation (GABA synthesis) step (UniProtKB:Q99259, GO:0004351) matches the completed human GAD1 review.
file:human/ABAT/ABAT-ai-review.yaml
ABAT gene review (human)
The GABA-transamination step (UniProtKB:P80404, GO:0034386) matches the completed human ABAT review.
file:human/ALDH5A1/ALDH5A1-ai-review.yaml
ALDH5A1 gene review (human)
The succinate-semialdehyde-dehydrogenase step (UniProtKB:P51649, GO:0004777) matches the completed human ALDH5A1 review.
PMID:11031268
Expression of a glutamate decarboxylase homologue is required for normal oxidative stress tolerance in Saccharomyces cerevisiae.
Identifies S. cerevisiae GAD1 as a plant-like, calmodulin-binding glutamate decarboxylase and UGA5 (UGA2) as succinate-semialdehyde dehydrogenase; the glutamate-to-succinate pathway is needed for normal oxidative stress tolerance.
The yeast GAD also bound to calmodulin as did the plant enzyme, suggesting a conservation of calcium regulation of this protein.
PMID:3888627
Mutations affecting the enzymes involved in the utilization of 4-aminobutyric acid as nitrogen source by the yeast Saccharomyces cerevisiae.
Genetic evidence that GABA transaminase and succinate-semialdehyde dehydrogenase make up the GABA utilization pathway of S. cerevisiae.
We present genetic evidence for the enzymes 4-aminobutyrate: 2-oxoglutarate aminotransferase (EC 2.6.1.19) and succinate-semialdehyde dehydrogenase [NAD(P)+] (EC 1.2.1.16) constituting the functional pathway for the utilization of 4-aminobutyric acid as a nitrogen source by Saccharomyces cerevisiae.
PMID:17355287
A gene duplication led to specialized gamma-aminobutyrate and beta-alanine aminotransferase in yeast.
Purified S. cerevisiae and S. pombe Uga1 are PLP-dependent GABA transaminases that use 2-oxoglutarate, not pyruvate, and do not transaminate beta-alanine.
SpUga1p and ScUga1p transaminate only GABA and not BAL.
PMID:19264755
Biochemical characterization, mitochondrial localization, expression, and potential functions for an Arabidopsis gamma-aminobutyrate transaminase that utilizes both pyruvate and glyoxylate.
The Arabidopsis GABA transaminase is mitochondrial and uses pyruvate and glyoxylate but not 2-oxoglutarate.
purified recombinant GABA-T has both pyruvate- and glyoxylate-dependent activities, but cannot utilize 2-oxoglutarate as amino acceptor.
PMID:12859897
Pollen tube growth and guidance is regulated by POP2, an Arabidopsis gene that controls GABA levels.
Arabidopsis POP2 encodes the GABA transaminase; pop2 flowers accumulate GABA and pollen tubes are misguided.
The Arabidopsis POP2 gene encodes a transaminase that degrades GABA and contributes to the formation of a gradient leading up to the micropyle.
PMID:10517851
Plant succinic semialdehyde dehydrogenase. Cloning, purification, localization in mitochondria, and regulation by adenine nucleotides.
Arabidopsis SSADH1 is a mitochondrial matrix, NAD+-specific succinate-semialdehyde dehydrogenase.
Fractionation of plant mitochondria revealed its localization in the matrix.
8Nodes
3Parts
2Variant Sets
4Variants
5Annotons
2Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:gaba_shunt deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

9 gene-function check(s) reflected in core functions · 0 conflict(s) · 5 evidence or coverage gap(s) (23 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
gad_activity GAD1 (human, GAD67)
UniProtKB:Q99259
Family Representative 		glutamate decarboxylase activity
GO:0004351 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
gad_activity GAD2 (human, GAD65)
UniProtKB:Q05329
Family Representative 		glutamate decarboxylase activity
GO:0004351 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
plant_fungal_gad_activity GAD1 (Saccharomyces cerevisiae)
UniProtKB:Q04792
Family Representative 		glutamate decarboxylase activity
GO:0004351 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
plant_fungal_gad_activity GAD1 (Arabidopsis thaliana)
UniProtKB:Q42521
Family Representative 		glutamate decarboxylase activity
GO:0004351 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
abat_activity ABAT (human)
UniProtKB:P80404
Family Representative 		4-aminobutyrate:2-oxoglutarate transaminase activity
GO:0034386 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
abat_activity UGA1 (Saccharomyces cerevisiae)
UniProtKB:P17649
Family Representative 		4-aminobutyrate:2-oxoglutarate transaminase activity
GO:0034386 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
abat_activity uga1 (Schizosaccharomyces pombe)
UniProtKB:O13837
Family Representative 		4-aminobutyrate:2-oxoglutarate transaminase activity
GO:0034386 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
plant_gaba_t_activity POP2 (Arabidopsis thaliana)
UniProtKB:Q94CE5
Family Representative 		4-aminobutyrate:pyruvate transaminase activity
GO:0034387 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
aldh5a1_activity ALDH5A1 (human)
UniProtKB:P51649
Family Representative 		succinate-semialdehyde dehydrogenase [NAD(P)+] activity
GO:0009013 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
aldh5a1_activity UGA2 (Saccharomyces cerevisiae)
UniProtKB:P38067
Family Representative 		succinate-semialdehyde dehydrogenase [NAD(P)+] activity
GO:0009013 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
aldh5a1_activity ssd1 (Schizosaccharomyces pombe)
UniProtKB:Q9US47
Family Representative 		succinate-semialdehyde dehydrogenase [NAD(P)+] activity
GO:0009013 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
aldh5a1_activity ssd2 (Schizosaccharomyces pombe)
UniProtKB:Q9UTM8
Family Representative 		succinate-semialdehyde dehydrogenase [NAD(P)+] activity
GO:0009013 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
aldh5a1_activity SSADH1/ALDH5F1 (Arabidopsis thaliana)
UniProtKB:Q9SAK4
Family Representative 		succinate-semialdehyde dehydrogenase [NAD(P)+] activity
GO:0009013 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
gad_activity Animal glutamate decarboxylase family (GAD1/GAD2)
PANTHER:PTHR45677:SF5
Family 		glutamate decarboxylase activity
GO:0004351 		Family Supported
Family review supports GO:0004351 for PANTHER:PTHR45677:SF5. Asserted by gaba_shunt; accepted by GAD1, gad1a and gad1b.
gad_activity Animal glutamate decarboxylase family (GAD1/GAD2)
PANTHER:PTHR45677:SF15
Family 		glutamate decarboxylase activity
GO:0004351 		Family Supported
Family review supports GO:0004351 for PANTHER:PTHR45677:SF15. Asserted by gaba_shunt; accepted by GAD1, gad1a and gad1b.
gad_activity Animal glutamate decarboxylase family (GAD1/GAD2)
PANTHER:PTHR45677:SF11
Family 		glutamate decarboxylase activity
GO:0004351 		Family Supported
Family review supports GO:0004351 for PANTHER:PTHR45677:SF11. Asserted by gaba_shunt; accepted by GAD1, gad1a and gad1b.
gad_activity Animal glutamate decarboxylase family (GAD1/GAD2)
PANTHER:PTHR45677:SF10
Family 		glutamate decarboxylase activity
GO:0004351 		Family Supported
Family review supports GO:0004351 for PANTHER:PTHR45677:SF10. Asserted by gaba_shunt; accepted by GAD1, gad1a and gad1b.
plant_fungal_gad_activity Plant and fungal glutamate decarboxylase family
PANTHER:PTHR43321
Family 		glutamate decarboxylase activity
GO:0004351 		Family Supported
Family review supports GO:0004351 FAMILY_WIDE. Asserted by gaba_shunt; accepted by S. cerevisiae GAD1.
abat_activity 4-aminobutyrate aminotransferase family (ABAT/UGA1)
PANTHER:PTHR43206:SF1
Family 		4-aminobutyrate:2-oxoglutarate transaminase activity
GO:0034386 		Family Supported
Family review supports GO:0034386 for PANTHER:PTHR43206:SF1. Asserted by gaba_shunt; accepted by ABAT, UGA1 and uga1.
abat_activity 4-aminobutyrate aminotransferase family (ABAT/UGA1)
PANTHER:PTHR43206:SF4
Family 		4-aminobutyrate:2-oxoglutarate transaminase activity
GO:0034386 		Family Supported
Family review supports GO:0034386 for PANTHER:PTHR43206:SF4. Asserted by gaba_shunt; accepted by ABAT, UGA1 and uga1.
plant_gaba_t_activity Plant pyruvate-dependent GABA transaminase (class III aminotransferase)
PANTHER:PTHR42684
Family 		4-aminobutyrate:pyruvate transaminase activity
GO:0034387 		Family Function Unreviewed
Family review leaves GO:0034387 UNRESOLVED. The plant mitochondrial GABA transaminases only: Arabidopsis POP2 (SF3), tomato GABA-TP1-3 and rice GABA-T (SF3, SF8, SF10, SF19, SF20). PAINT asserts no GABA-transaminase node in this family. The gaba_shunt module's POP2 annoton uses the family id PTHR42684, which also selects every BioA and BIO3. As with BioA, a required_function or member-level selector is needed.
aldh5a1_activity Succinate-semialdehyde dehydrogenase family (ALDH5A1/UGA2)
PANTHER:PTHR43353:SF5
Family 		succinate-semialdehyde dehydrogenase [NAD(P)+] activity
GO:0009013 		Family Supported
Family review supports GO:0009013 for PANTHER:PTHR43353:SF5. Asserted by gaba_shunt; accepted by ALDH5A1, UGA2, ssd1 and ssd2.
aldh5a1_activity Succinate-semialdehyde dehydrogenase family (ALDH5A1/UGA2)
PANTHER:PTHR43353:SF12
Family 		succinate-semialdehyde dehydrogenase [NAD(P)+] activity
GO:0009013 		Family Supported
Family review supports GO:0009013 for PANTHER:PTHR43353:SF12. Asserted by gaba_shunt; accepted by ALDH5A1, UGA2, ssd1 and ssd2.

Gene-review completeness (9/13 grounded genes reviewed)

5 complete review(s) · 3 with deep research · 4 missing review · 6 reviewed but lacking deep research

Gene Review Complete Deep research
ABAT P80404 ✓ ✓ ✗
ALDH5A1 P51649 ✓ ✓ ✗
GAD1 Q04792 ✓ ✓ ✓
GAD1 Q99259 ✓ 46/50 ✗
GAD2 (human, GAD65) Q05329 ✗ — —
GAD1 (Arabidopsis thaliana) Q42521 ✗ — —
POP2 (Arabidopsis thaliana) Q94CE5 ✗ — —
SSADH1/ALDH5F1 (Arabidopsis thaliana) Q9SAK4 ✗ — —
ssd1 Q9US47 ✓ 13/14 ✗
ssd2 Q9UTM8 ✓ 12/14 ✗
uga1 O13837 ✓ 11/12 ✗
UGA1 P17649 ✓ ✓ ✓
UGA2 P38067 ✓ ✓ ✓

Details

Context
animalsNCBITaxon:33208 green plantsNCBITaxon:33090 fungiNCBITaxon:4751
GABA shunt (glutamate to GABA to succinate)Metabolic Pathwaygaba_shunt
GABA shuntGO:0006540
Context
animalsNCBITaxon:33208 green plantsNCBITaxon:33090 fungiNCBITaxon:4751

GENERALIZED (YeastPathways crosswalk, 2026-10) from the earlier mammalian module to cover fungi and plants. The mammalian realization is kept as the animal lineage variant: human GAD1/GAD2 (PTHR45677), ABAT (P80404) and ALDH5A1 (P51649), grounded in the human Reactome reactions and the completed human gene reviews. In mammals GAD is cytosolic, while ABAT and ALDH5A1 are in the mitochondrial matrix, so GABA must be imported. GAD1 deficiency causes spastic paraplegia, cerebral palsy or developmental and epileptic encephalopathy, ABAT deficiency causes GABA-transaminase deficiency, and ALDH5A1 deficiency causes SSADH deficiency (4-hydroxybutyric aciduria). ABAT also transaminates beta-amino acids, which links it to thymine catabolism. In yeasts that function belongs to a separate paralog in the S. kluyveri lineage (PYD4; PMID:17355287). Fungal grounding: S. cerevisiae GAD1, UGA1 and UGA2 (YeastCyc GLUDEG-I-PWY-1 and YEAST-4AMINOBUTMETAB-PWY; all three gene assignments retained). S. pombe uga1, ssd1 and ssd2 come from the PomBase GABA-catabolism model. YeastCyc corrections: none to gene content. The GLUDEG-I-PWY-1 comment notes that GDH2 glutamate dehydrogenase, not this shunt, is the main route of glutamate degradation in S. cerevisiae. Compartments differ by lineage. S. cerevisiae UGA1 and UGA2 are cytosolic (UniProt, PMID:11914276, PMID:14562095), whereas the PomBase model places S. pombe uga1, ssd1 and ssd2 in the mitochondrial matrix. Because of this, no location is asserted on the catabolic annotons. GO-CAM disagreements: the PomBase model types ssd1/ssd2 as NAD+-specific (GO:0004777), while UniProt names them NADP+-dependent. The SGD models have no causal links. The PomBase model's plasma-membrane and mitochondrial GABA import activities are enabled by unidentified proteins and are outside the module. S. pombe has no glutamate decarboxylase, so the GAD part is optional. The uptake permeases (S. cerevisiae UGA4, PUT4, GAP1) and the UGA3/DAL81 transcriptional control are excluded. Scope: eukaryotic GABA shunt; the bacterial GabT/GabD pathway (for example in P. putida) and its transport and regulation belong in a separate bacterial module.

Connections

gad_step -> abat_step Provides Input For
abat_step -> aldh5a1_step Provides Input For
Part 1: GABA synthesis (glutamate decarboxylation) (optional)

Optional because some lineages lack glutamate decarboxylase. For example, S. pombe has no glutamate decarboxylase in UniProt and its PomBase model starts from imported GABA.

L-glutamate to GABA + CO2Reactiongad_step
Variant set: Animal versus plant/fungal glutamate decarboxylase families by enzyme family (lineage) (Exactly One)

Both families are PLP-dependent group II decarboxylases with the same activity, but PANTHER puts them in different families: animal GAD1 and GAD2 in PTHR45677, and the plant and fungal enzymes in PTHR43321. The plant and yeast enzymes bind calmodulin.

Animal glutamate decarboxylases (GAD1/GAD2)Reactionanimal_gad

Annotons

GAD1/GAD2: glutamate decarboxylase
gad_activity
Participant: Family: Animal glutamate decarboxylase family (GAD1/GAD2)
Family:
Animal glutamate decarboxylase family (GAD1/GAD2)
Representative Members: GAD1 (human, GAD67)UniProtKB:Q99259 GAD2 (human, GAD65)UniProtKB:Q05329

Function

glutamate decarboxylase activityGO:0004351
Substrates: L-glutamate
Products: gamma-aminobutyric acid (GABA) CO2

Locations

cytosolGO:0005829

PLP-dependent decarboxylation of glutamate to the inhibitory neurotransmitter GABA. GAD1 (GAD67) is the constitutive cytosolic isoform; GAD2 (GAD65) is membrane-associated at synaptic vesicles. GAD1 deficiency -> spastic paraplegia / cerebral palsy / epileptic encephalopathy.

Calmodulin-binding plant and fungal glutamate decarboxylasesReactionplant_fungal_gad

Annotons

Plant/fungal glutamate decarboxylase
plant_fungal_gad_activity
Participant: Family: Plant and fungal glutamate decarboxylase family
Family:
Plant and fungal glutamate decarboxylase familyPANTHER:PTHR43321
Representative Members: GAD1 (Saccharomyces cerevisiae)UniProtKB:Q04792 GAD1 (Arabidopsis thaliana)UniProtKB:Q42521

Function

glutamate decarboxylase activityGO:0004351
Substrates: L-glutamate
Products: gamma-aminobutyric acid (GABA) CO2

Locations

cytosolGO:0005829

PLP-dependent glutamate decarboxylase with a C-terminal calmodulin-binding region; in yeast it supplies GABA for the shunt that buffers oxidative stress.

PMID:11031268
S. cerevisiae GAD1 is a plant-like glutamate decarboxylase.
we identify a Saccharomyces cerevisiae homologue of the GABA-producing enzyme glutamate decarboxylase (GAD) that is required for normal oxidative stress tolerance.
Part 2: GABA transamination (first catabolic step)
GABA + acceptor 2-oxo acid to succinate semialdehyde + amino acidReactionabat_step
Variant set: 2-oxoglutarate-dependent versus pyruvate-dependent GABA transaminase by amino-group acceptor (enzyme family) (One Or More)

Animal and fungal GABA transaminases (PTHR43206) use 2-oxoglutarate, so the transamination regenerates the glutamate consumed by GAD and closes the shunt. The main plant enzyme (POP2, PTHR42684) uses pyruvate or glyoxylate, giving alanine or glycine instead.

2-oxoglutarate-dependent GABA transaminase (ABAT/UGA1)Reactionoxoglutarate_gaba_t

Annotons

ABAT/UGA1: 4-aminobutyrate:2-oxoglutarate aminotransferase
abat_activity
Participant: Family: 4-aminobutyrate aminotransferase family (ABAT/UGA1)
Family:
4-aminobutyrate aminotransferase family (ABAT/UGA1)
Representative Members: ABAT (human)UniProtKB:P80404 UGA1 (Saccharomyces cerevisiae)UniProtKB:P17649 uga1 (Schizosaccharomyces pombe)UniProtKB:O13837

Function

4-aminobutyrate:2-oxoglutarate transaminase activityGO:0034386
Substrates: gamma-aminobutyric acid (GABA) 2-oxoglutarate
Products: succinate semialdehyde L-glutamate

Processes

GABA catabolic processGO:0009450

PLP-dependent GABA transaminase: transfers GABA's amino group to 2-oxoglutarate, yielding succinate semialdehyde and regenerating glutamate. Human ABAT is in the mitochondrial matrix (deficiency = GABA-transaminase deficiency); S. cerevisiae UGA1 is cytosolic. No location is asserted for the role because it differs between lineages.

PMID:17355287
S. cerevisiae and S. pombe Uga1 use 2-oxoglutarate as amino acceptor.
alpha-ketoglutarate, and not pyruvate, as the amino group acceptor.
Pyruvate/glyoxylate-dependent GABA transaminase (plants)Reactionpyruvate_gaba_t

Annotons

POP2: 4-aminobutyrate:pyruvate aminotransferase
plant_gaba_t_activity
Participant: Family: Plant pyruvate-dependent GABA transaminase (class III aminotransferase)
Family:
Plant pyruvate-dependent GABA transaminase (class III aminotransferase)PANTHER:PTHR42684
Representative Members: POP2 (Arabidopsis thaliana)UniProtKB:Q94CE5

Function

4-aminobutyrate:pyruvate transaminase activityGO:0034387
Substrates: gamma-aminobutyric acid (GABA) pyruvate
Products: succinate semialdehyde L-alanine

Processes

GABA catabolic processGO:0009450

Locations

mitochondrial matrixGO:0005759

Mitochondrial plant GABA transaminase that uses pyruvate or glyoxylate, not 2-oxoglutarate. pop2 mutants accumulate GABA in flowers and show defective pollen-tube guidance.

PMID:19264755
Arabidopsis GABA-T uses pyruvate and glyoxylate, not 2-oxoglutarate.
cannot utilize 2-oxoglutarate as amino acceptor.
PMID:12859897
POP2 encodes the Arabidopsis GABA-degrading transaminase.
Arabidopsis POP2 gene encodes a transaminase that degrades GABA
Part 3: oxidation to succinate (feeds TCA cycle)
succinate semialdehyde + NAD(P)+ to succinate + NAD(P)HReactionaldh5a1_step

Annotons

ALDH5A1/UGA2: succinate-semialdehyde dehydrogenase (SSADH)
aldh5a1_activity
Participant: Family: Succinate-semialdehyde dehydrogenase family (ALDH5A1/UGA2)
Family:
Succinate-semialdehyde dehydrogenase family (ALDH5A1/UGA2)
Representative Members: ALDH5A1 (human)UniProtKB:P51649 UGA2 (Saccharomyces cerevisiae)UniProtKB:P38067 ssd1 (Schizosaccharomyces pombe)UniProtKB:Q9US47 ssd2 (Schizosaccharomyces pombe)UniProtKB:Q9UTM8 SSADH1/ALDH5F1 (Arabidopsis thaliana)UniProtKB:Q9SAK4

Function

succinate-semialdehyde dehydrogenase [NAD(P)+] activityGO:0009013
Substrates: succinate semialdehyde NAD+ or NADP+
Products: succinate NADH or NADPH

Processes

GABA catabolic processGO:0009450

Oxidation of succinate semialdehyde to succinate, which enters the TCA cycle, completing the GABA shunt. The step is annotated with the cofactor-neutral term GO:0009013 because the animal and plant enzymes are NAD+-specific (GO:0004777, a child term) while the yeast enzymes are named NADP+-dependent. Human deficiency = SSADH deficiency (4-hydroxybutyric / GHB aciduria). The enzyme is in the mitochondrial matrix in animals and plants and in the cytosol in S. cerevisiae.

PMID:10517851
Plant SSADH1 is NAD+-specific.
exclusively used NAD+ as a cofactor