4-aminobenzoate biosynthesis I

MetaCyc:PWY-6543

4-Aminobenzoate biosynthesis I converts chorismate and L-glutamine to 4-aminobenzoate through 4-amino-4-deoxychorismate.

Pathway type

cofactor biosynthesis

Organism scope

Escherichia coli NCBITaxon:562

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Pathway network

16 nodes · 16 asserted directed edges

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Reaction / activity
Chemical / cofactor
Protein / complex
Other participant
Solid arrow: mechanistic relation
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 `NCBITaxon:562`	taxon
aminodeoxychorismate synthase `EC:2.6.1.85`	molecular activity
aminodeoxychorismate lyase `EC:4.1.3.38`	molecular activity
chorismate `CHEBI:29748`	small molecule
L-glutamine `CHEBI:58359`	small molecule
4-amino-4-deoxychorismate `CHEBI:58406`	small molecule
L-glutamate `CHEBI:29985`	small molecule
4-aminobenzoate `CHEBI:17836`	small molecule
pyruvate `CHEBI:15361`	small molecule
H+ `CHEBI:15378`	small molecule
Aminodeoxychorismate synthase component 2 `UniProtKB:P00903`	protein
Aminodeoxychorismate synthase component 1 `UniProtKB:P05041`	protein
magnesium(2+) `CHEBI:18420`	cofactor
Aminodeoxychorismate lyase `UniProtKB:P28305`	protein
pyridoxal 5'-phosphate(2-) `CHEBI:597326`	cofactor
aminodeoxychorismate synthase reaction `RHEA:11673`	reaction	left to right
aminodeoxychorismate lyase reaction `RHEA:16202`	reaction	left to right

Mechanistic edges

Mechanistic edges and their cited evidence
Subject	Predicate and description	Object	Evidence
chorismate `CHEBI:29748`	consumes	aminodeoxychorismate synthase reaction `RHEA:11673`	RHEA:11673 Source assertion: Rhea lists CHEBI:29748 on the substrates side of RHEA:11673 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/11673']/rh:substrates; rh:contains/rh:compound/rh:accession`
L-glutamine `CHEBI:58359`	consumes	aminodeoxychorismate synthase reaction `RHEA:11673`	RHEA:11673 Source assertion: Rhea lists CHEBI:58359 on the substrates side of RHEA:11673 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/11673']/rh:substrates; rh:contains/rh:compound/rh:accession`
aminodeoxychorismate synthase reaction `RHEA:11673`	produces	L-glutamate `CHEBI:29985`	RHEA:11673 Source assertion: Rhea lists CHEBI:29985 on the products side of RHEA:11673 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/11673']/rh:products; rh:contains/rh:compound/rh:accession`
aminodeoxychorismate synthase reaction `RHEA:11673`	produces	4-amino-4-deoxychorismate `CHEBI:58406`	RHEA:11673 Source assertion: Rhea lists CHEBI:58406 on the products side of RHEA:11673 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/11673']/rh:products; rh:contains/rh:compound/rh:accession`
4-amino-4-deoxychorismate `CHEBI:58406`	consumes	aminodeoxychorismate lyase reaction `RHEA:16202`	RHEA:16202 Source assertion: Rhea lists CHEBI:58406 on the substrates side of RHEA:16202 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/16202']/rh:substrates; rh:contains/rh:compound/rh:accession`
aminodeoxychorismate lyase reaction `RHEA:16202`	produces	pyruvate `CHEBI:15361`	RHEA:16202 Source assertion: Rhea lists CHEBI:15361 on the products side of RHEA:16202 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/16202']/rh:products; rh:contains/rh:compound/rh:accession`
aminodeoxychorismate lyase reaction `RHEA:16202`	produces	H+ `CHEBI:15378`	RHEA:16202 Source assertion: Rhea lists CHEBI:15378 on the products side of RHEA:16202 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/16202']/rh:products; rh:contains/rh:compound/rh:accession`
aminodeoxychorismate lyase reaction `RHEA:16202`	produces	4-aminobenzoate `CHEBI:17836`	RHEA:16202 Source assertion: Rhea lists CHEBI:17836 on the products side of RHEA:16202 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/16202']/rh:products; rh:contains/rh:compound/rh:accession`
aminodeoxychorismate synthase `EC:2.6.1.85`	catalyzes	aminodeoxychorismate synthase reaction `RHEA:11673`	RHEA:11672 Source assertion: Rhea associates EC:2.6.1.85 with the reaction family containing RHEA:11673. Source location `rh:ec` PMID:1644759 Aminodeoxychorismate synthase components I and II, encoded by pabB and pabA, respectively, convert chorismate and glutamine to 4-amino-4-deoxychorismate (ADC) and glutamate, respectively. Source location `PubMed Abstract`
aminodeoxychorismate lyase `EC:4.1.3.38`	catalyzes	aminodeoxychorismate lyase reaction `RHEA:16202`	RHEA:16201 Source assertion: Rhea associates EC:4.1.3.38 with the reaction family containing RHEA:16202. Source location `rh:ec` PMID:2251281 Enzyme X shows no activity on chorismate but quantitatively converts the preformed aminodeoxychorismate into p-aminobenzoate and pyruvate, acting thereby as an aminodeoxychorismate lyase. Source location `PubMed Abstract`
aminodeoxychorismate synthase reaction `RHEA:11673`	precedes	aminodeoxychorismate lyase reaction `RHEA:16202`	MetaCyc:PWY-6543 Source assertion: MetaCyc pathway ordering places RHEA:11673 before RHEA:16202 in this pathway. Shared intermediate: CHEBI:58406. Source location `Pathway/reaction-ordering and reaction-layout; Rhea-to-MetaCyc cross-references`
Aminodeoxychorismate synthase component 2 `UniProtKB:P00903`	enables	aminodeoxychorismate synthase reaction `RHEA:11673`	UniProtKB:P00903 Source assertion: UniProt annotates UniProtKB:P00903 with catalytic activity for the reaction family of RHEA:11673. Annotation evidence: ECO:0000269, ECO:0000305; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Aminodeoxychorismate synthase component 1 `UniProtKB:P05041`	enables	aminodeoxychorismate synthase reaction `RHEA:11673`	UniProtKB:P05041 Source assertion: UniProt annotates UniProtKB:P05041 with catalytic activity for the reaction family of RHEA:11673. Annotation evidence: ECO:0000269; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Aminodeoxychorismate synthase component 1 `UniProtKB:P05041`	has_cofactor	magnesium(2+) `CHEBI:18420`	UniProtKB:P05041 Source assertion: UniProt lists CHEBI:18420 as a cofactor of UniProtKB:P05041 (evidence: ECO:0000269). Source location `comments[commentType='COFACTOR'].cofactors and note`
Aminodeoxychorismate lyase `UniProtKB:P28305`	enables	aminodeoxychorismate lyase reaction `RHEA:16202`	UniProtKB:P28305 Source assertion: UniProt annotates UniProtKB:P28305 with catalytic activity for the reaction family of RHEA:16202. Annotation evidence: ECO:0000269; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Aminodeoxychorismate lyase `UniProtKB:P28305`	has_cofactor	pyridoxal 5'-phosphate(2-) `CHEBI:597326`	UniProtKB:P28305 Source assertion: UniProt lists CHEBI:597326 as a cofactor of UniProtKB:P28305 (evidence: ECO:0000269). Source location `comments[commentType='COFACTOR'].cofactors and note`

References

MetaCyc:PWY-6543 MetaCyc 4-aminobenzoate biosynthesis I pathway (source version: 22.5)
RHEA:11672 Rhea aminodeoxychorismate synthase reaction (source version: 139)
RHEA:11673 Rhea left-to-right aminodeoxychorismate synthase direction (source version: 139)
RHEA:16201 Rhea aminodeoxychorismate lyase reaction (source version: 139)
RHEA:16202 Rhea 4-amino-4-deoxychorismate-to-4-aminobenzoate lyase direction (source version: 139)
PMID:2251281 Green and Nichols, Proceedings of the National Academy of Sciences, 1990
PMID:1644759 Green et al., Journal of Bacteriology, 1992
UniProtKB:P00903 UniProtKB:P00903 authority record (source version: 2026_03)
UniProtKB:P05041 UniProtKB:P05041 authority record (source version: 2026_03)
UniProtKB:P28305 UniProtKB:P28305 authority record (source version: 2026_03)

Curation history

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 2 to 2; 0 directed-ID corrections; 3 protein annotations, 2 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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