2,3-dihydroxybenzoate biosynthesis

MetaCyc:PWY-5901

The complete three-step pathway converts chorismate to 2,3-dihydroxybenzoate through isochorismate and (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate. It follows the exact MetaCyc PWY-5901 boundary and the experimentally resolved EntC–EntB–EntA sequence in Escherichia coli K-12. EntC is an active monomer; its reversible chemistry is oriented toward biosynthesis. EntB contributes its N-terminal isochorismatase activity, represented by the native holo-EntB dimer with two explicitly modified protein components. That form does not establish a requirement for phosphopantetheinylation of its separate carrier domain in DHB production. EntA uses NAD and produces DHB by oxidation followed by rapid aromatization, represented once as the net reaction. Its selected native tetramer coexists with concentration-dependent dimer–tetramer behavior; an older octamer estimate remains a historical conflict. Magnesium annotations are retained for EntC and EntB with their stated evidence limits. K-12 mutant physiology and reviewed K-12 proteins ground the taxon; native MG1655 assembly attribution does not relabel every experiment as MG1655. Upstream chorismate biosynthesis, downstream EntB carrier maturation/loading and enterobactin assembly, and the extra CueO-associated oxidation on the broader PathBank map are outside this independently defined pathway. Pairwise EntC–EntB interaction does not establish obligatory substrate channeling or a fixed multienzyme assembly.

Pathway type

2 3 dihydroxybenzoate biosynthesis

Organism scope

Escherichia coli K-12 NCBITaxon:83333

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Pathway network

19 nodes · 23 asserted directed edges

Arrows show recorded subject → object relationships, not necessarily metabolic flow. Select a node for details or an arrow for evidence. Scroll, zoom or find a node to explore.

Reaction / activity
Chemical / cofactor
Protein / complex
Pathway
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 K-12 `NCBITaxon:83333`	taxon
pyruvate `CHEBI:15361`	small molecule
water `CHEBI:15377`	small molecule
hydron `CHEBI:15378`	small molecule
magnesium(2+) `CHEBI:18420`	cofactor
chorismate(2-) `CHEBI:29748`	small molecule
isochorismate(2-) `CHEBI:29780`	small molecule
2,3-dihydroxybenzoate `CHEBI:36654`	small molecule
NAD(1-) `CHEBI:57540`	small molecule
NADH(2-) `CHEBI:57945`	small molecule
(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate `CHEBI:58764`	small molecule
Isochorismate synthase EntC `UniProtKB:P0AEJ2`	protein
2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase `UniProtKB:P15047`	protein
holo EntB `MetaCyc:HOLO-ENTB`	protein
holo-EntB dimer `MetaCyc:ENTB-CPLX`	complex
2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase `MetaCyc:ENTA-CPLX`	complex
chorismate => isochorismate `RHEA:18986`	molecular activity	left to right
isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	molecular activity	left to right
(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	molecular activity	left to right

Mechanistic edges

Mechanistic edges and their cited evidence
Subject	Predicate and description	Object	Evidence
chorismate(2-) `CHEBI:29748`	consumes	chorismate => isochorismate `RHEA:18986`	RHEA:18986 Source assertion: RHEA:18986 assigns CHEBI:29748 to its substrates, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/18986 rh:substrates; http://rdf.rhea-db.org/18985_L rh:contains1 http://rdf.rhea-db.org/Participant_18985_compound_3304; http://rdf.rhea-db.org/Participant_18985_compound_3304 rh:compound http://rdf.rhea-db.org/Compound_3304; rh:chebi`
chorismate => isochorismate `RHEA:18986`	produces	isochorismate(2-) `CHEBI:29780`	RHEA:18986 Source assertion: RHEA:18986 assigns CHEBI:29780 to its products, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/18986 rh:products; http://rdf.rhea-db.org/18985_R rh:contains1 http://rdf.rhea-db.org/Participant_18985_compound_3577; http://rdf.rhea-db.org/Participant_18985_compound_3577 rh:compound http://rdf.rhea-db.org/Compound_3577; rh:chebi`
isochorismate(2-) `CHEBI:29780`	consumes	isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	RHEA:11113 Source assertion: RHEA:11113 assigns CHEBI:29780 to its substrates, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/11113 rh:substrates; http://rdf.rhea-db.org/11112_L rh:contains1 http://rdf.rhea-db.org/Participant_11112_compound_3577; http://rdf.rhea-db.org/Participant_11112_compound_3577 rh:compound http://rdf.rhea-db.org/Compound_3577; rh:chebi`
water `CHEBI:15377`	consumes	isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	RHEA:11113 Source assertion: RHEA:11113 assigns CHEBI:15377 to its substrates, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/11113 rh:substrates; http://rdf.rhea-db.org/11112_L rh:contains1 http://rdf.rhea-db.org/Participant_11112_compound_1283; http://rdf.rhea-db.org/Participant_11112_compound_1283 rh:compound http://rdf.rhea-db.org/Compound_1283; rh:chebi`
isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	produces	(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate `CHEBI:58764`	RHEA:11113 Source assertion: RHEA:11113 assigns CHEBI:58764 to its products, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/11113 rh:products; http://rdf.rhea-db.org/11112_R rh:contains1 http://rdf.rhea-db.org/Participant_11112_compound_5459; http://rdf.rhea-db.org/Participant_11112_compound_5459 rh:compound http://rdf.rhea-db.org/Compound_5459; rh:chebi`
isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	produces	pyruvate `CHEBI:15361`	RHEA:11113 Source assertion: RHEA:11113 assigns CHEBI:15361 to its products, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/11113 rh:products; http://rdf.rhea-db.org/11112_R rh:contains1 http://rdf.rhea-db.org/Participant_11112_compound_3719; http://rdf.rhea-db.org/Participant_11112_compound_3719 rh:compound http://rdf.rhea-db.org/Compound_3719; rh:chebi`
(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate `CHEBI:58764`	consumes	(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	RHEA:23825 Source assertion: RHEA:23825 assigns CHEBI:58764 to its substrates, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/23825 rh:substrates; http://rdf.rhea-db.org/23824_L rh:contains1 http://rdf.rhea-db.org/Participant_23824_compound_5459; http://rdf.rhea-db.org/Participant_23824_compound_5459 rh:compound http://rdf.rhea-db.org/Compound_5459; rh:chebi`
NAD(1-) `CHEBI:57540`	consumes	(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	RHEA:23825 Source assertion: RHEA:23825 assigns CHEBI:57540 to its substrates, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/23825 rh:substrates; http://rdf.rhea-db.org/23824_L rh:contains1 http://rdf.rhea-db.org/Participant_23824_compound_3484; http://rdf.rhea-db.org/Participant_23824_compound_3484 rh:compound http://rdf.rhea-db.org/Compound_3484; rh:chebi`
(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	produces	2,3-dihydroxybenzoate `CHEBI:36654`	RHEA:23825 Source assertion: RHEA:23825 assigns CHEBI:36654 to its products, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/23825 rh:products; http://rdf.rhea-db.org/23824_R rh:contains1 http://rdf.rhea-db.org/Participant_23824_compound_3751; http://rdf.rhea-db.org/Participant_23824_compound_3751 rh:compound http://rdf.rhea-db.org/Compound_3751; rh:chebi`
(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	produces	NADH(2-) `CHEBI:57945`	RHEA:23825 Source assertion: RHEA:23825 assigns CHEBI:57945 to its products, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/23825 rh:products; http://rdf.rhea-db.org/23824_R rh:contains1 http://rdf.rhea-db.org/Participant_23824_compound_1650; http://rdf.rhea-db.org/Participant_23824_compound_1650 rh:compound http://rdf.rhea-db.org/Compound_1650; rh:chebi`
(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	produces	hydron `CHEBI:15378`	RHEA:23825 Source assertion: RHEA:23825 assigns CHEBI:15378 to its products, coefficient 1 via rh:contains1. Source location `http://rdf.rhea-db.org/23825 rh:products; http://rdf.rhea-db.org/23824_R rh:contains1 http://rdf.rhea-db.org/Participant_23824_compound_3249; http://rdf.rhea-db.org/Participant_23824_compound_3249 rh:compound http://rdf.rhea-db.org/Compound_3249; rh:chebi`
Isochorismate synthase EntC `UniProtKB:P0AEJ2`	catalyzes The selected forward reaction supplies isochorismate to DHB synthesis. EntC is reversible; this direction is not a claim of irreversible chemistry. Purified EntC itself is active, so the protein node has direct catalytic support.	chorismate => isochorismate `RHEA:18986`	UniProtKB:P0AEJ2 Source assertion: Reviewed K-12 EntC assigns chorismate/isochorismate interconversion to RHEA:18985 with ECO:0000269 citations 17243787, 20079748 and 2139795; SUBUNIT specifies monomer. Source location `/organism/taxonId; /comments/1/reaction; /comments/5` MetaCyc:ENTC-MONOMER Source assertion: ENTC-MONOMER catalyzes ISOCHORSYN-RXN through ENTC-ENZRXN and explicitly unifies UniProt P0AEJ2. Source location `Protein[@frameid="ENTC-MONOMER"]/catalyzes/Enzymatic-Reaction[@frameid="ENTC-ENZRXN"]/reaction; dblink[dblink-db="UNIPROT"]` PMID:2139795 Source assertion: Purified E. coli EntC is an active monomer and alone catalyzes reversible chorismate/isochorismate interconversion; EntA does not alter that activity. The measured equilibrium favors chorismate. Source location `/resultList/result[id="2139795"]/abstractText` RHEA:18986 Source assertion: Master RHEA:18985 explicitly links directionalReaction RHEA:18986. Source location `http://rdf.rhea-db.org/18985 rh:directionalReaction http://rdf.rhea-db.org/18986`
holo-EntB dimer `MetaCyc:ENTB-CPLX`	catalyzes The catalyst is the exact source-defined holo-EntB dimer. This retains a supported active form without asserting that phosphopantetheinylation of the separate carrier domain is necessary for isochorismatase activity or that apo-EntB lacks that activity.	isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	MetaCyc:ENTB-CPLX Source assertion: The native holo-EntB dimer catalyzes ISOCHORMAT-RXN through ISOCHORMAT-ENZRXN. Its N-terminal domain is the isochorismatase; its C-terminal aryl carrier domain participates later in enterobactin assembly. Source location `Protein[@frameid="ENTB-CPLX"]/catalyzes/Enzymatic-Reaction[@frameid="ISOCHORMAT-ENZRXN"]/reaction; comment` UniProtKB:P0ADI4 Source assertion: K-12 EntB CATALYTIC ACTIVITY assigns RHEA:11112, isochorismate plus water to the (2S,3S) dihydroxy-dihydrobenzoate and pyruvate, with ECO:0000269 citations 16632253, 2139796, 9214294 and 9485415. Source location `/organism/taxonId; /comments/2/reaction` PMID:2139796 Source assertion: Purified recombinant EntB catalyzes the isochorismate reaction; proton NMR followed the expected dihydro-dihydroxybenzoate product. This experiment assigns the protein activity, not a requirement for carrier-domain phosphopantetheinylation. Source location `/resultList/result[id="2139796"]/abstractText` RHEA:11113 Source assertion: Master RHEA:11112 explicitly links directionalReaction RHEA:11113. Source location `http://rdf.rhea-db.org/11112 rh:directionalReaction http://rdf.rhea-db.org/11113`
2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase `MetaCyc:ENTA-CPLX`	catalyzes One net reaction includes the subsequent rapid aromatization; a separate aromatization edge would double count the selected net chemistry. NAD is a consumed redox cosubstrate, not an additional bound-cofactor claim.	(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	MetaCyc:ENTA-CPLX Source assertion: ENTA-CPLX catalyzes DHBDEHYD-RXN through DHBDEHYD-ENZRXN; its comment distinguishes C3 oxidation and rapid aromatization from the net DHB-forming reaction. Source location `Protein[@frameid="ENTA-CPLX"]/catalyzes/Enzymatic-Reaction[@frameid="DHBDEHYD-ENZRXN"]/reaction; comment` UniProtKB:P15047 Source assertion: K-12 EntA CATALYTIC ACTIVITY assigns RHEA:23824 and the exact (2S,3S) dihydroxy-dihydrobenzoate/NAD reaction with ECO:0000269 PMID:2144454. Source location `/organism/taxonId; /comments/1/reaction` PMID:2144454 Source assertion: EntA oxidizes the C3 hydroxyl with NAD; the transient keto intermediate aromatizes to DHB. Reversibility was demonstrated with substrate analogues, not by demonstrating physiological reduction of aromatic DHB. Source location `/resultList/result[id="2144454"]/abstractText` RHEA:23825 Source assertion: Master RHEA:23824 explicitly links directionalReaction RHEA:23825. Source location `http://rdf.rhea-db.org/23824 rh:directionalReaction http://rdf.rhea-db.org/23825`
2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase `UniProtKB:P15047`	part_of Four EntA subunits define the selected native complex. The record does not claim that the tetramer is the only populated or catalytically competent state. PathBank preserves an older eight-subunit interpretation that is not imported as the selected assembly.	2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase `MetaCyc:ENTA-CPLX`	MetaCyc:ENTA-CPLX Source assertion: The native assembly contains four ENTA-MONOMER components. Its comment preserves the older gel-filtration octamer estimate, tetrameric crystal structure and later concentration-dependent dimer-to-tetramer transition. Source location `Protein[@frameid="ENTA-CPLX"]/component/Protein; component/coefficient; comment` MetaCyc:ENTA-MONOMER Source assertion: ENTA-MONOMER explicitly unifies UniProt P15047 and has native MG1655 taxonomic provenance. Source location `Protein[@frameid="ENTA-MONOMER"]/dblink[dblink-db="UNIPROT"]; species/Organism` UniProtKB:P15047 Source assertion: SUBUNIT annotates a homotetramer, a dimer of dimers, with ECO:0000269 citations 16790929, 21166461 and 2521622. Source location `/comments/5` PMID:21166461 Source assertion: Analytical ultracentrifugation shows concentration-dependent EntA dimer-tetramer self-association, with a reported dissociation constant of 12.3 micromolar; this is not evidence that only one assembly exists. Source location `/resultList/result[id="21166461"]/abstractText` PMID:2521622 Source assertion: The 1989 purified preparation migrated at an estimated native mass of 210,000 on Superose 12, interpreted as an octamer. This historical estimate is retained as a conflicting assembly result. Source location `PMC209666 full PDF p.795, Results/Purification of diDHB-DH; p.796 Discussion`
holo EntB `MetaCyc:HOLO-ENTB`	part_of Two modified EntB protein components are retained under their exact native state identifier. Their underlying sequence is P0ADI4. Carrier maturation and aryl loading belong to the surrounding enterobactin pathway and are not added as DHB-biosynthesis steps.	holo-EntB dimer `MetaCyc:ENTB-CPLX`	MetaCyc:ENTB-CPLX Source assertion: ENTB-CPLX contains two HOLO-ENTB components. The comment identifies phosphopantetheinylated carrier-domain holo-EntB and records the modern dimer assignment versus earlier trimer/pentamer estimates. Source location `Protein[@frameid="ENTB-CPLX"]/component/Protein[@frameid="HOLO-ENTB"]; component/coefficient; comment` MetaCyc:HOLO-ENTB Source assertion: HOLO-ENTB explicitly names ENTB-MONOMER as its unmodified form and ENTB-CPLX as its containing assembly. Source location `Protein[@frameid="HOLO-ENTB"]/unmodified-form; component-of` MetaCyc:ENTB-MONOMER Source assertion: The unmodified ENTB-MONOMER explicitly unifies UniProt P0ADI4. Its comment distinguishes the N-terminal isochorismatase from the C-terminal aryl carrier domain and EntD-dependent carrier maturation. Source location `Protein[@frameid="ENTB-MONOMER"]/dblink[dblink-db="UNIPROT"]; comment` UniProtKB:P0ADI4 Source assertion: SUBUNIT specifies homodimer citing PMID:16632253 with ECO:0000269. Its wider EntB/EntD/EntE/EntF synthase association concerns downstream enterobactin assembly. Source location `/comments/7`
Isochorismate synthase EntC `UniProtKB:P0AEJ2`	has_cofactor Magnesium binding is an explicit reviewed experimental annotation; it is not inferred merely from an assay containing magnesium.	magnesium(2+) `CHEBI:18420`	UniProtKB:P0AEJ2 Source assertion: COFACTOR explicitly names Mg(2+), CHEBI:18420, and states two magnesium ions per subunit, with ECO:0000269 PMID:20079748. Source location `/comments/2/cofactors; /comments/2/note` PMID:20079748 Source assertion: The primary abstract reports an EntC structure in complex with isochorismate and Mg(2+) at 2.3 angstrom resolution. The two-ion count is sourced to the separate reviewed UniProt annotation, not this abstract. Source location `/resultList/result[id="20079748"]/abstractText`
holo-EntB dimer `MetaCyc:ENTB-CPLX`	has_cofactor This is the reviewed EntB magnesium-cofactor annotation, retained at the source-defined dimer. The inspected primary abstract does not independently establish metal dependence or an occupancy count; crystallographic magnesium sites alone are not treated as a stoichiometric requirement.	magnesium(2+) `CHEBI:18420`	UniProtKB:P0ADI4 Source assertion: COFACTOR explicitly names Mg(2+), CHEBI:18420, with ECO:0000269 PMID:16632253; no occupancy count is asserted by this annotation. Source location `/comments/3/cofactors` MetaCyc:ENTB-CPLX Source assertion: The source-defined EntB dimer is the isochorismatase catalyst; its two HOLO-ENTB components are the modified forms of the P0ADI4 gene product. Source location `Protein[@frameid="ENTB-CPLX"]/catalyzes/Enzymatic-Reaction[@frameid="ISOCHORMAT-ENZRXN"]; component` MetaCyc:HOLO-ENTB Source assertion: HOLO-ENTB explicitly links to unmodified ENTB-MONOMER. Source location `Protein[@frameid="HOLO-ENTB"]/unmodified-form` MetaCyc:ENTB-MONOMER Source assertion: ENTB-MONOMER explicitly unifies UniProt P0ADI4. Source location `Protein[@frameid="ENTB-MONOMER"]/dblink[dblink-db="UNIPROT"]`
chorismate => isochorismate `RHEA:18986`	part_of	`MetaCyc:PWY-5901`	MetaCyc:PWY-5901 Source assertion: The complete native pathway explicitly lists ISOCHORSYN-RXN and orients it left-to-right in its pathway layout. Source location `Pathway[@frameid="PWY-5901"]/reaction-list; reaction-layout` MetaCyc:ISOCHORSYN-RXN Source assertion: ISOCHORSYN-RXN explicitly cross-references RHEA:18988; its native chemistry and pathway orientation identify the selected reaction. Source location `Reaction[@frameid="ISOCHORSYN-RXN"]/dblink[dblink-db="RHEA"]; reaction-direction; left; right` RHEA:18986 Source assertion: Master RHEA:18985 links directionalReaction RHEA:18986 and bidirectionalReaction RHEA:18988; the native reversible reaction is projected in its pathway synthesis direction. Source location `http://rdf.rhea-db.org/18985 rh:directionalReaction http://rdf.rhea-db.org/18986; rh:bidirectionalReaction http://rdf.rhea-db.org/18988`
isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	part_of	`MetaCyc:PWY-5901`	MetaCyc:PWY-5901 Source assertion: The complete native pathway explicitly lists ISOCHORMAT-RXN and orients it left-to-right in its pathway layout. Source location `Pathway[@frameid="PWY-5901"]/reaction-list; reaction-layout` MetaCyc:ISOCHORMAT-RXN Source assertion: ISOCHORMAT-RXN explicitly cross-references RHEA:11112; its native chemistry and pathway orientation identify the selected reaction. Source location `Reaction[@frameid="ISOCHORMAT-RXN"]/dblink[dblink-db="RHEA"]; reaction-direction; left; right` RHEA:11113 Source assertion: Master RHEA:11112 explicitly links directionalReaction RHEA:11113. Source location `http://rdf.rhea-db.org/11112 rh:directionalReaction http://rdf.rhea-db.org/11113`
(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	part_of	`MetaCyc:PWY-5901`	MetaCyc:PWY-5901 Source assertion: The complete native pathway explicitly lists DHBDEHYD-RXN and orients it left-to-right in its pathway layout. Source location `Pathway[@frameid="PWY-5901"]/reaction-list; reaction-layout` MetaCyc:DHBDEHYD-RXN Source assertion: DHBDEHYD-RXN explicitly cross-references RHEA:23825; its native chemistry and pathway orientation identify the selected reaction. Source location `Reaction[@frameid="DHBDEHYD-RXN"]/dblink[dblink-db="RHEA"]; reaction-direction; left; right` RHEA:23825 Source assertion: Master RHEA:23824 explicitly links directionalReaction RHEA:23825. Source location `http://rdf.rhea-db.org/23824 rh:directionalReaction http://rdf.rhea-db.org/23825`
chorismate => isochorismate `RHEA:18986`	precedes Biochemical ordering through a shared small-molecule intermediate; no obligate channeling or stable multienzyme complex is asserted.	isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	MetaCyc:PWY-5901 Source assertion: Native reaction ordering places ISOCHORSYN-RXN before ISOCHORMAT-RXN; the shared native intermediate connects the two complete transformations. Source location `Pathway[@frameid="PWY-5901"]/reaction-ordering` RHEA:18986 Source assertion: RHEA:18986 has CHEBI:29780 on its products side via its participant and compound objects. Source location `http://rdf.rhea-db.org/18986 rh:products http://rdf.rhea-db.org/18985_R; http://rdf.rhea-db.org/18985_R rh:contains1 http://rdf.rhea-db.org/Participant_18985_compound_3577; rh:compound http://rdf.rhea-db.org/Compound_3577; rh:chebi` RHEA:11113 Source assertion: RHEA:11113 has CHEBI:29780 on its substrates side via its participant and compound objects. Source location `http://rdf.rhea-db.org/11113 rh:substrates http://rdf.rhea-db.org/11112_L; http://rdf.rhea-db.org/11112_L rh:contains1 http://rdf.rhea-db.org/Participant_11112_compound_3577; rh:compound http://rdf.rhea-db.org/Compound_3577; rh:chebi` PMID:4928016 Source assertion: K-12 mutant extract complementation and intermediate accumulation resolve the EntC, EntB and EntA sequence from chorismate through isochorismate and dihydro-dihydroxybenzoate to DHB. Source location `PMC248643 full PDF pp.54-55, Identification of enzyme deficiency; Tables 2 and 3`
isochorismate + H2O => (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate `RHEA:11113`	precedes Biochemical ordering through a shared small-molecule intermediate; no obligate channeling or stable multienzyme complex is asserted.	(2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + NAD(+) => 2,3-dihydroxybenzoate + NADH + H(+) `RHEA:23825`	MetaCyc:PWY-5901 Source assertion: Native reaction ordering places ISOCHORMAT-RXN before DHBDEHYD-RXN; the shared native intermediate connects the two complete transformations. Source location `Pathway[@frameid="PWY-5901"]/reaction-ordering` RHEA:11113 Source assertion: RHEA:11113 has CHEBI:58764 on its products side via its participant and compound objects. Source location `http://rdf.rhea-db.org/11113 rh:products http://rdf.rhea-db.org/11112_R; http://rdf.rhea-db.org/11112_R rh:contains1 http://rdf.rhea-db.org/Participant_11112_compound_5459; rh:compound http://rdf.rhea-db.org/Compound_5459; rh:chebi` RHEA:23825 Source assertion: RHEA:23825 has CHEBI:58764 on its substrates side via its participant and compound objects. Source location `http://rdf.rhea-db.org/23825 rh:substrates http://rdf.rhea-db.org/23824_L; http://rdf.rhea-db.org/23824_L rh:contains1 http://rdf.rhea-db.org/Participant_23824_compound_5459; rh:compound http://rdf.rhea-db.org/Compound_5459; rh:chebi` PMID:4928016 Source assertion: K-12 mutant extract complementation and intermediate accumulation resolve the EntC, EntB and EntA sequence from chorismate through isochorismate and dihydro-dihydroxybenzoate to DHB. Source location `PMC248643 full PDF pp.54-55, Identification of enzyme deficiency; Tables 2 and 3`

References

RHEA:18986 Rhea directional reaction 18986 (source version: Rhea 142, 2026-09-02; digest covers complete compressed RDF, with exact subjects selected by evidence locators)
RHEA:11113 Rhea directional reaction 11113 (source version: Rhea 142, 2026-09-02; digest covers complete compressed RDF, with exact subjects selected by evidence locators)
RHEA:23825 Rhea directional reaction 23825 (source version: Rhea 142, 2026-09-02; digest covers complete compressed RDF, with exact subjects selected by evidence locators)
UniProtKB:P0AEJ2 Isochorismate synthase EntC (source version: Reviewed UniProt 2026_03; complete JSON retrieved 2026-10-11 UTC)
MetaCyc:ENTC-MONOMER MetaCyc ENTC-MONOMER: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
PMID:2139795 Overexpression, purification, and characterization of isochorismate synthase (EntC), the first enzyme involved in the biosynthesis of enterobactin from chorismate. (source version: 1990; indexed abstract in retained Europe PMC core JSON, not full article)
MetaCyc:ENTB-CPLX MetaCyc ENTB-CPLX: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
UniProtKB:P0ADI4 Enterobactin synthase component B (source version: Reviewed UniProt 2026_03; complete JSON retrieved 2026-10-11 UTC)
PMID:2139796 Subcloning of the enterobactin biosynthetic gene entB: expression, purification, characterization, and substrate specificity of isochorismatase. (source version: 1990; indexed abstract in retained Europe PMC core JSON, not full article)
MetaCyc:ENTA-CPLX MetaCyc ENTA-CPLX: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
UniProtKB:P15047 2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase (source version: Reviewed UniProt 2026_03; complete JSON retrieved 2026-10-11 UTC)
PMID:2144454 Mechanistic studies on trans-2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase (Ent A) in the biosynthesis of the iron chelator enterobactin. (source version: 1990; indexed abstract in retained Europe PMC core JSON, not full article)
MetaCyc:ENTA-MONOMER MetaCyc ENTA-MONOMER: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
PMID:21166461 Enzymatic adenylation of 2,3-dihydroxybenzoate is enhanced by a protein-protein interaction between Escherichia coli 2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase (EntA) and 2,3-dihydroxybenzoate-AMP ligase (EntE). (source version: 2011; indexed abstract in retained Europe PMC core JSON, not full article)
PMID:2521622 Nucleotide sequence of a cluster of Escherichia coli enterobactin biosynthesis genes: identification of entA and purification of its product 2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase. (source version: 1989; complete scanned primary PDF, independently extracted and rendered; retrieved 2026-10-11 UTC)
MetaCyc:HOLO-ENTB MetaCyc HOLO-ENTB: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
MetaCyc:ENTB-MONOMER MetaCyc ENTB-MONOMER: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
PMID:20079748 Crystal structure of Escherichia coli enterobactin-specific isochorismate synthase (EntC) bound to its reaction product isochorismate: implications for the enzyme mechanism and differential activity of chorismate-utilizing enzymes. (source version: 2010; indexed abstract in retained Europe PMC core JSON, not full article)
MetaCyc:PWY-5901 MetaCyc PWY-5901: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
MetaCyc:ISOCHORSYN-RXN MetaCyc ISOCHORSYN-RXN: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
MetaCyc:ISOCHORMAT-RXN MetaCyc ISOCHORMAT-RXN: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
MetaCyc:DHBDEHYD-RXN MetaCyc DHBDEHYD-RXN: exact native definition (source version: MetaCyc 22.5; complete native XML retrieved 2026-10-11 UTC)
PMID:4928016 Biosynthesis of the iron-transport compound enterochelin: mutants of Escherichia coli unable to synthesize 2,3-dihydroxybenzoate. (source version: 1971; complete scanned primary PDF, independently extracted and rendered; retrieved 2026-10-11 UTC)

Curation history

2026-10-11T06:10:35Z codex
- CREATE — Curated complete MetaCyc:PWY-5901 pathway network
  Complete three-reaction native boundary; source-state holo EntB components, EntA assembly disagreement, and excluded neighboring PathBank scope are explicitly retained. Record SHA256 94a671009cfae9c61381d26067a07e80edaeb5d6e4f73a00ae8c81bfb35b1144. Evidence bodies, exact replays and source dispositions are retained in research/pathway_additions/2026-10-11-next-195. Shared authority integration, generated pages, full local gates and independent scientific reviews are subsequent checks; this CREATE event does not claim their completion.
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2026-10-11T06:21:56Z codex
- EDIT — Correct the historical EntA Discussion page citation
  Resolved the supported locator correction from initial review 20261011T061848Z-dhb-initial-independent-review: dhb-edge-015 PMID2521622 supplementary Discussion pointer changes from printed page797 to796; Results page795 remains. Scientific assertions, nodes, edges and chemistry are unchanged. Initial target/dossiers are retained under research/pathway_additions/2026-10-11-next-195/initial-review-inputs/dhb. Final YAML SHA256 bdb60326e2ffa5db8e15939ce29bf57a12b992c1f2e56899c1cec3ecf01e2859. Exact locator guard and full author source replay passed; independent successor and final corpus gates are subsequent checks.
Read this curation session