D-galacturonate degradation I

MetaCyc:GALACTUROCAT-PWY

D-galacturonate degradation I isomerizes aldehydo-D-galacturonate to keto-D-tagaturonate, reduces it to D-altronate, dehydrates and phosphorylates it to 2-dehydro-3-deoxy-6-phospho-D-gluconate, and cleaves that phosphorylated intermediate to D-glyceraldehyde 3-phosphate and pyruvate.

Pathway type

carbohydrate degradation

Organism scope

Escherichia coli str. K-12 substr. MG1655 NCBITaxon:511145

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Pathway network

23 nodes · 27 asserted directed edges

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Reaction / activity
Chemical / cofactor
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Dashed arrow: membership, location or cofactor relation

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Components and activities

Declared biological components and source reaction directions
Node	Kind or role	Source direction
Escherichia coli str. K-12 substr. MG1655 `NCBITaxon:511145`	taxon
glucuronate isomerase `EC:5.3.1.12`	molecular activity
tagaturonate reductase `EC:1.1.1.58`	molecular activity
altronate dehydratase `EC:4.2.1.7`	molecular activity
2-dehydro-3-deoxygluconokinase `EC:2.7.1.45`	molecular activity
2-dehydro-3-deoxy-phosphogluconate aldolase `EC:4.1.2.14`	molecular activity
aldehydo-D-galacturonate `CHEBI:12952`	small molecule
keto-D-tagaturonate `CHEBI:17886`	small molecule
NADH `CHEBI:57945`	small molecule
H(+) `CHEBI:15378`	small molecule
NAD(+) `CHEBI:57540`	small molecule
D-altronate `CHEBI:17360`	small molecule
2-dehydro-3-deoxy-D-gluconate `CHEBI:57990`	small molecule
H2O `CHEBI:15377`	small molecule
ATP `CHEBI:30616`	small molecule
2-dehydro-3-deoxy-6-phospho-D-gluconate `CHEBI:57569`	small molecule
ADP `CHEBI:456216`	small molecule
D-glyceraldehyde 3-phosphate `CHEBI:59776`	small molecule
pyruvate `CHEBI:15361`	small molecule
altronate dehydratase reaction `RHEA:15958`	reaction	left to right
2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	reaction	left to right
2-dehydro-3-deoxy-6-phosphogluconate aldolase reaction `RHEA:17090`	reaction	left to right
D-galacturonate isomerase reaction `RHEA:27703`	reaction	left to right
tagaturonate reductase reaction `RHEA:17815`	reaction	right to left

Mechanistic edges

Mechanistic edges and their cited evidence
Subject	Predicate and description	Object	Evidence
D-altronate `CHEBI:17360`	consumes	altronate dehydratase reaction `RHEA:15958`	RHEA:15958 Source assertion: Rhea lists CHEBI:17360 on the substrates side of RHEA:15958 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/15958']/rh:substrates; rh:contains/rh:compound/rh:accession`
altronate dehydratase reaction `RHEA:15958`	produces	H2O `CHEBI:15377`	RHEA:15958 Source assertion: Rhea lists CHEBI:15377 on the products side of RHEA:15958 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/15958']/rh:products; rh:contains/rh:compound/rh:accession`
altronate dehydratase reaction `RHEA:15958`	produces	2-dehydro-3-deoxy-D-gluconate `CHEBI:57990`	RHEA:15958 Source assertion: Rhea lists CHEBI:57990 on the products side of RHEA:15958 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/15958']/rh:products; rh:contains/rh:compound/rh:accession`
ATP `CHEBI:30616`	consumes	2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	RHEA:14798 Source assertion: Rhea lists CHEBI:30616 on the substrates side of RHEA:14798 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/14798']/rh:substrates; rh:contains/rh:compound/rh:accession`
2-dehydro-3-deoxy-D-gluconate `CHEBI:57990`	consumes	2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	RHEA:14798 Source assertion: Rhea lists CHEBI:57990 on the substrates side of RHEA:14798 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/14798']/rh:substrates; rh:contains/rh:compound/rh:accession`
2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	produces	H(+) `CHEBI:15378`	RHEA:14798 Source assertion: Rhea lists CHEBI:15378 on the products side of RHEA:14798 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/14798']/rh:products; rh:contains/rh:compound/rh:accession`
2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	produces	ADP `CHEBI:456216`	RHEA:14798 Source assertion: Rhea lists CHEBI:456216 on the products side of RHEA:14798 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/14798']/rh:products; rh:contains/rh:compound/rh:accession`
2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	produces	2-dehydro-3-deoxy-6-phospho-D-gluconate `CHEBI:57569`	RHEA:14798 Source assertion: Rhea lists CHEBI:57569 on the products side of RHEA:14798 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/14798']/rh:products; rh:contains/rh:compound/rh:accession`
2-dehydro-3-deoxy-6-phospho-D-gluconate `CHEBI:57569`	consumes	2-dehydro-3-deoxy-6-phosphogluconate aldolase reaction `RHEA:17090`	RHEA:17090 Source assertion: Rhea lists CHEBI:57569 on the substrates side of RHEA:17090 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/17090']/rh:substrates; rh:contains/rh:compound/rh:accession`
2-dehydro-3-deoxy-6-phosphogluconate aldolase reaction `RHEA:17090`	produces	pyruvate `CHEBI:15361`	RHEA:17090 Source assertion: Rhea lists CHEBI:15361 on the products side of RHEA:17090 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/17090']/rh:products; rh:contains/rh:compound/rh:accession`
2-dehydro-3-deoxy-6-phosphogluconate aldolase reaction `RHEA:17090`	produces	D-glyceraldehyde 3-phosphate `CHEBI:59776`	RHEA:17090 Source assertion: Rhea lists CHEBI:59776 on the products side of RHEA:17090 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/17090']/rh:products; rh:contains/rh:compound/rh:accession`
aldehydo-D-galacturonate `CHEBI:12952`	consumes	D-galacturonate isomerase reaction `RHEA:27703`	RHEA:27703 Source assertion: Rhea lists CHEBI:12952 on the substrates side of RHEA:27703 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/27703']/rh:substrates; rh:contains/rh:compound/rh:accession`
D-galacturonate isomerase reaction `RHEA:27703`	produces	keto-D-tagaturonate `CHEBI:17886`	RHEA:27703 Source assertion: Rhea lists CHEBI:17886 on the products side of RHEA:27703 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/27703']/rh:products; rh:contains/rh:compound/rh:accession`
H(+) `CHEBI:15378`	consumes	tagaturonate reductase reaction `RHEA:17815`	RHEA:17815 Source assertion: Rhea lists CHEBI:15378 on the substrates side of RHEA:17815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/17815']/rh:substrates; rh:contains/rh:compound/rh:accession`
keto-D-tagaturonate `CHEBI:17886`	consumes	tagaturonate reductase reaction `RHEA:17815`	RHEA:17815 Source assertion: Rhea lists CHEBI:17886 on the substrates side of RHEA:17815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/17815']/rh:substrates; rh:contains/rh:compound/rh:accession`
NADH `CHEBI:57945`	consumes	tagaturonate reductase reaction `RHEA:17815`	RHEA:17815 Source assertion: Rhea lists CHEBI:57945 on the substrates side of RHEA:17815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/17815']/rh:substrates; rh:contains/rh:compound/rh:accession`
tagaturonate reductase reaction `RHEA:17815`	produces	D-altronate `CHEBI:17360`	RHEA:17815 Source assertion: Rhea lists CHEBI:17360 on the products side of RHEA:17815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/17815']/rh:products; rh:contains/rh:compound/rh:accession`
tagaturonate reductase reaction `RHEA:17815`	produces	NAD(+) `CHEBI:57540`	RHEA:17815 Source assertion: Rhea lists CHEBI:57540 on the products side of RHEA:17815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/17815']/rh:products; rh:contains/rh:compound/rh:accession`
glucuronate isomerase `EC:5.3.1.12`	catalyzes	D-galacturonate isomerase reaction `RHEA:27703`	RHEA:27702 Source assertion: Rhea associates EC:5.3.1.12 with the reaction family containing RHEA:27703. Source location `rh:ec`
tagaturonate reductase `EC:1.1.1.58`	catalyzes	tagaturonate reductase reaction `RHEA:17815`	RHEA:17813 Source assertion: Rhea associates EC:1.1.1.58 with the reaction family containing RHEA:17815. Source location `rh:ec`
altronate dehydratase `EC:4.2.1.7`	catalyzes	altronate dehydratase reaction `RHEA:15958`	RHEA:15957 Source assertion: Rhea associates EC:4.2.1.7 with the reaction family containing RHEA:15958. Source location `rh:ec`
2-dehydro-3-deoxygluconokinase `EC:2.7.1.45`	catalyzes	2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	RHEA:14797 Source assertion: Rhea associates EC:2.7.1.45 with the reaction family containing RHEA:14798. Source location `rh:ec`
2-dehydro-3-deoxy-phosphogluconate aldolase `EC:4.1.2.14`	catalyzes	2-dehydro-3-deoxy-6-phosphogluconate aldolase reaction `RHEA:17090`	RHEA:17089 Source assertion: Rhea associates EC:4.1.2.14 with the reaction family containing RHEA:17090. Source location `rh:ec`
2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	precedes	2-dehydro-3-deoxy-6-phosphogluconate aldolase reaction `RHEA:17090`	MetaCyc:GALACTUROCAT-PWY Source assertion: MetaCyc pathway ordering places RHEA:14798 before RHEA:17090 in this pathway. Shared intermediate: CHEBI:57569. Source location `Pathway/reaction-ordering and reaction-layout; Rhea-to-MetaCyc cross-references`
altronate dehydratase reaction `RHEA:15958`	precedes	2-dehydro-3-deoxygluconokinase reaction `RHEA:14798`	MetaCyc:GALACTUROCAT-PWY Source assertion: MetaCyc pathway ordering places RHEA:15958 before RHEA:14798 in this pathway. Shared intermediate: CHEBI:57990. Source location `Pathway/reaction-ordering and reaction-layout; Rhea-to-MetaCyc cross-references`
tagaturonate reductase reaction `RHEA:17815`	precedes	altronate dehydratase reaction `RHEA:15958`	MetaCyc:GALACTUROCAT-PWY Source assertion: MetaCyc pathway ordering places RHEA:17815 before RHEA:15958 in this pathway. Shared intermediate: CHEBI:17360. Source location `Pathway/reaction-ordering and reaction-layout; Rhea-to-MetaCyc cross-references`
D-galacturonate isomerase reaction `RHEA:27703`	precedes	tagaturonate reductase reaction `RHEA:17815`	MetaCyc:GALACTUROCAT-PWY Source assertion: MetaCyc pathway ordering places RHEA:27703 before RHEA:17815 in this pathway. Shared intermediate: CHEBI:17886. Source location `Pathway/reaction-ordering and reaction-layout; Rhea-to-MetaCyc cross-references`

References

MetaCyc:GALACTUROCAT-PWY MetaCyc D-galacturonate degradation I (source version: 22.5)
RHEA:27702 Rhea D-galacturonate isomerase reaction (source version: 139)
RHEA:27705 Rhea bidirectional D-galacturonate isomerase reaction (source version: 139)
RHEA:17813 Rhea tagaturonate reductase reaction (source version: 139)
RHEA:17816 Rhea bidirectional tagaturonate reductase reaction (source version: 139)
RHEA:15957 Rhea altronate dehydratase reaction (source version: 139)
RHEA:15958 Rhea altronate-dehydrating direction (source version: 139)
RHEA:14797 Rhea 2-dehydro-3-deoxygluconokinase reaction (source version: 139)
RHEA:14798 Rhea 2-dehydro-3-deoxy-6-phospho-D-gluconate-forming direction (source version: 139)
RHEA:17089 Rhea 2-dehydro-3-deoxy-6-phosphogluconate aldolase reaction (source version: 139)
RHEA:17090 Rhea 2-dehydro-3-deoxy-6-phosphogluconate-cleaving direction (source version: 139)
RHEA:27703 RHEA:27703 authority record (source version: 139)
RHEA:17815 RHEA:17815 authority record (source version: 139)

Curation history

2026-10-05T04:18:15Z codex
- EDIT — Align NCBITaxon:511145 label with the pinned authority
  Corrected the taxon label from Escherichia coli K-12 substr. MG1655 to Escherichia coli str. K-12 substr. MG1655, matching the independently extracted NCBITaxon 2026-05-13 canonical label in data/identifier_authorities/ontology.json. The identifier and biological scope are unchanged. Discovered by the blocking identifier gate for issue #229; tracked by #243.
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2026-10-05T06:25:52Z codex
- EDIT — Review causal chemistry and add sourced molecular context
  Reviewed the entire record against MetaCyc 22.5 native pathway XML (including nested pathways), Rhea 139 explicit sides and directions, ENZYME 02-Sep-2026, PubMed records, and reviewed UniProt 2026_03 annotations within the record's taxon scope. Replaced generated structured-source quotations with source_assertion and source_locator. Typed molecular activities and participants. Reaction count 5 to 5; 2 directed-ID corrections; 0 protein annotations, 0 cofactor annotations and 0 sourced locations. All Rhea reaction substrate/product sets checked against independent Rhea authority; native pathway leaf coverage and source exceptions recorded in reports/causal_graph_review/metacyc-review.json. Full source URLs, versions and byte hashes are in metacyc-sources.json. All 50 MetaCyc records passed native schema validation; six targeted chemistry/evidence regression tests passed. Missing protein or cofactor annotations are not treated as biological absence; qualifications and exclusions are preserved in the ledger.
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