glutamate synthase complex (NADPH)

GO:0009342 · Other · Multiprotein complex · Proposed

A NADPH-dependent glutamate synthase protein complex that possesses glutamate synthase (NADPH) activity. [GO:0009342]

Synonyms: Glutamate synthase [NADPH] complex; GOGAT complex; Iron-sulfur flavoenzyme glutamate synthase complex; Glutamine-oxoglutarate amino transferase complex

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
Glutamate synthase NADPH large chain	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	gltB		UNKNOWN	Large glutamate synthase subunit that binds glutamine and participates in amide transfer to 2-oxoglutarate in the NADPH-dependent GltBD complex. `UniProtKB:P09831` Reviewed E. coli K-12 GltB accession. `PMID:3326786` Oliver et al. 1987 identified the E. coli K-12 large subunit structural gene. `ComplexPortal:CPX-5041` Complex Portal CPX-5041 curates P09831/GltB as a protein participant in the E. coli K-12 glutamate synthase [NADPH] complex.
Glutamate synthase NADPH small chain	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	gltD		UNKNOWN	Small iron-sulfur glutamate synthase subunit in the NADPH-dependent GltBD complex. `UniProtKB:P09832` Reviewed E. coli K-12 GltD accession. `PMID:3326786` Oliver et al. 1987 identified the E. coli K-12 small subunit structural gene. `ComplexPortal:CPX-5041` Complex Portal CPX-5041 curates P09832/GltD as a protein participant in the E. coli K-12 glutamate synthase [NADPH] complex.

Organism-specific protein examples

Named proteins in which each component's role was established, with the organism the evidence comes from. The component above is the taxon-agnostic family; these are the specific entries behind it.

Glutamate synthase NADPH large chain

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P09831`	Glutamate synthase [NADPH] large chain	gltB	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (2 references) Reviewed E. coli K-12 GltB accession for the NADPH-dependent glutamate synthase large chain. `UniProtKB:P09831` UniProtKB P09831 is the reviewed E. coli K-12 entry for the NADPH-dependent glutamate synthase large chain. `PMID:3326786` Oliver et al. 1987 sequenced the E. coli K-12 glutamate synthase structural genes for both large and small subunits.

Glutamate synthase NADPH small chain

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P09832`	Glutamate synthase [NADPH] small chain	gltD	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (2 references) Reviewed E. coli K-12 GltD accession for the NADPH-dependent glutamate synthase small chain. `UniProtKB:P09832` UniProtKB P09832 is the reviewed E. coli K-12 entry for the NADPH-dependent glutamate synthase small chain. `PMID:3326786` Oliver et al. 1987 sequenced the E. coli K-12 glutamate synthase structural genes for both large and small subunits.

Source composition assertions

Glutamate synthase [NADPH] complex (ComplexPortal:CPX-5041)

Escherichia coli (strain K12) (NCBITaxon:83333) · ECO:0000353 · retrieved 2026-10-02

Participant	Source type	Source name	Stoichiometry
`UniProtKB:P09831` — Glutamate synthase [NADPH] large chain	protein	gltB	not asserted
`UniProtKB:P09832` — Glutamate synthase [NADPH] small chain	protein	gltD	not asserted
`CHEBI:49883` — tetra-mu3-sulfido-tetrairon	small molecule	4Fe-4S iron-sulfur cluster	1

Canonical examples

NCBITaxon:83333 Escherichia coli K-12 — Source strain for the CPX-5041 GltBD composition and the reviewed UniProtKB GltB and GltD examples. [ComplexPortal:CPX-5041]

Functions

glutamate synthase (NADPH) activity GO:0004355 — NADPH-dependent conversion mediated by the GltBD complex between glutamine plus 2-oxoglutarate and glutamate.
- GO:0009342 GO:0009342 is the cellular-component term for a complex that possesses glutamate synthase (NADPH) activity.
- GO:0004355 GO:0004355 is the molecular-function term for glutamate synthase (NADPH) activity.
- PMID:4565085 Miller and Stadtman 1972 characterized purified E. coli glutamate synthase as an iron-sulfur flavoprotein.

Discussions

CURATION_TODO (OPEN): Can the GltB and GltD components be grounded to exact source-neutral families? GltB has only domain/broad dehydrogenase signatures in the reviewed E. coli UniProtKB entry, and the closest reviewed GltD InterPro family also covers AegA/UacF oxidoreductase relatives. Keep both components reviewed-label-only until exact large-chain and small-chain families are verified.

Evidence

GO:0009342 Gene Ontology cellular-component term for the NADPH-specific glutamate synthase complex.
GO:0031026 OLS4 reports GO:0009342 as an is-a child of the generic glutamate synthase complex term GO:0031026.
GO:0004355 Gene Ontology molecular-function term for glutamate synthase (NADPH) activity.
UniProtKB:P09831 Reviewed UniProtKB E. coli K-12 GltB entry.
UniProtKB:P09832 Reviewed UniProtKB E. coli K-12 GltD entry.
ComplexPortal:CPX-5041 Complex Portal entry for the E. coli K-12 glutamate synthase [NADPH] complex.
PMID:4565085 PubMed identifier for Miller and Stadtman 1972, the Journal of Biological Chemistry biochemical study cited by GO:0009342 and CPX-5041.
DOI:10.1016/S0021-9258(19)44642-5 DOI for Miller and Stadtman 1972 as reported by UniProtKB.
PMID:3326786 PubMed identifier for Oliver et al. 1987, the E. coli K-12 glutamate synthase structural-gene sequence paper.
DOI:10.1016/0378-1119(87)90207-1 DOI for Oliver et al. 1987, as reported by PubMed.

Curation history

2026-10-02T03:41:45Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-02T03:43:16Z codex · EXPANDED_RECORD — Added GO parentage, Complex Portal synonymy and E. coli K-12 composition, reviewed-label-only GltB/GltD constituents, reviewed UniProt examples, glutamate synthase NADPH activity, a component grounding TODO, and DOI/PMID evidence.
2026-10-05T00:17:05Z codex · CORRECTED_METADATA — Issue #2043: preserve 1 nonprotein Complex Portal source name(s) in source_name instead of gene_symbol; identities, labels, taxa, membership and stoichiometry unchanged.

Source: data/structures/other/glutamate_synthase_complex_nadph.yaml