cyanate degradation

MetaCyc:CYANCAT-PWY

The CynS/CynT bicarbonate-recycling route annotated for Escherichia coli K-12 MG1655 converts cyanate to ammonium and carbon dioxide. The cyanase homodecamer first forms carbamate from cyanate and bicarbonate; carbamate then decomposes spontaneously. Zinc-containing CynT hydrates carbon dioxide to replenish bicarbonate. The graph selects this physiological hydration direction of a reversible reaction. K-12 mutant experiments support the recycling role at 0.03% CO2, with rescue of the cynT deletion at 3% CO2; they do not establish an unconditional requirement for CynT. This record represents the explicit intermediate route, not an additional parallel net cyanase reaction.

Pathway type

cyanate catabolism and bicarbonate recycling

Organism scope

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

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Pathway network

17 nodes · 26 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
Cell / process context
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 str. K-12 substr. MG1655 `NCBITaxon:511145`	taxon
cyanate `CHEBI:29195`	small molecule
hydrogencarbonate `CHEBI:17544`	small molecule
hydron `CHEBI:15378`	small molecule
carbamate `CHEBI:13941`	small molecule
carbon dioxide `CHEBI:16526`	small molecule
ammonium `CHEBI:28938`	small molecule
water `CHEBI:15377`	small molecule
zinc(2+) `CHEBI:29105`	cofactor
Cyanate hydratase `UniProtKB:P00816`	protein
Carbonic anhydrase 1 `UniProtKB:P0ABE9`	protein
cyanase `MetaCyc:CYANLY-CPLX`	complex
carbonic anhydrase 1 `MetaCyc:CARBODEHYDRAT-CPLX`	complex
cytoplasm `GO:0005737`	cellular component
cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	molecular activity	left to right
carbamate + 2 H(+) => NH4(+) + CO2 `RHEA:15650`	reaction	left to right
CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	molecular activity	right to left

Mechanistic edges

Mechanistic edges and their cited evidence
Subject	Predicate and description	Object	Evidence
cyanate `CHEBI:29195`	consumes	cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	RHEA:18490 Source assertion: Rhea RHEA:18490 assigns CHEBI:29195 to its substrates, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/18490']/rh:substrates; rdf:Description[@rdf:about='http://rdf.rhea-db.org/18489_L']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_18489_compound_1057']; rh:compound/rh:chebi`
hydrogencarbonate `CHEBI:17544`	consumes	cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	RHEA:18490 Source assertion: Rhea RHEA:18490 assigns CHEBI:17544 to its substrates, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/18490']/rh:substrates; rdf:Description[@rdf:about='http://rdf.rhea-db.org/18489_L']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_18489_compound_1123']; rh:compound/rh:chebi`
hydron `CHEBI:15378`	consumes	cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	RHEA:18490 Source assertion: Rhea RHEA:18490 assigns CHEBI:15378 to its substrates, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/18490']/rh:substrates; rdf:Description[@rdf:about='http://rdf.rhea-db.org/18489_L']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_18489_compound_3249']; rh:compound/rh:chebi`
cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	produces	carbamate `CHEBI:13941`	RHEA:18490 Source assertion: Rhea RHEA:18490 assigns CHEBI:13941 to its products, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/18490']/rh:products; rdf:Description[@rdf:about='http://rdf.rhea-db.org/18489_R']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_18489_compound_4239']; rh:compound/rh:chebi`
cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	produces	carbon dioxide `CHEBI:16526`	RHEA:18490 Source assertion: Rhea RHEA:18490 assigns CHEBI:16526 to its products, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/18490']/rh:products; rdf:Description[@rdf:about='http://rdf.rhea-db.org/18489_R']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_18489_compound_4391']; rh:compound/rh:chebi`
carbamate `CHEBI:13941`	consumes	carbamate + 2 H(+) => NH4(+) + CO2 `RHEA:15650`	RHEA:15650 Source assertion: Rhea RHEA:15650 assigns CHEBI:13941 to its substrates, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/15650']/rh:substrates; rdf:Description[@rdf:about='http://rdf.rhea-db.org/15649_L']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_15649_compound_4239']; rh:compound/rh:chebi` MetaCyc:RXN0-5222 Source assertion: MetaCyc RXN0-5222 explicitly sets spontaneous=true for carbamate decomposition to ammonium and carbon dioxide. Source location `Reaction[@frameid='RXN0-5222']/spontaneous; left; right`
hydron `CHEBI:15378`	consumes	carbamate + 2 H(+) => NH4(+) + CO2 `RHEA:15650`	RHEA:15650 Source assertion: Rhea RHEA:15650 assigns CHEBI:15378 to its substrates, with coefficient 2 in rh:contains2. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/15650']/rh:substrates; rdf:Description[@rdf:about='http://rdf.rhea-db.org/15649_L']/rh:contains2[@rdf:resource='http://rdf.rhea-db.org/Participant_15649_compound_3249']; rh:compound/rh:chebi` MetaCyc:RXN0-5222 Source assertion: MetaCyc RXN0-5222 explicitly sets spontaneous=true for carbamate decomposition to ammonium and carbon dioxide. Source location `Reaction[@frameid='RXN0-5222']/spontaneous; left; right`
carbamate + 2 H(+) => NH4(+) + CO2 `RHEA:15650`	produces	ammonium `CHEBI:28938`	RHEA:15650 Source assertion: Rhea RHEA:15650 assigns CHEBI:28938 to its products, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/15650']/rh:products; rdf:Description[@rdf:about='http://rdf.rhea-db.org/15649_R']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_15649_compound_1012']; rh:compound/rh:chebi` MetaCyc:RXN0-5222 Source assertion: MetaCyc RXN0-5222 explicitly sets spontaneous=true for carbamate decomposition to ammonium and carbon dioxide. Source location `Reaction[@frameid='RXN0-5222']/spontaneous; left; right`
carbamate + 2 H(+) => NH4(+) + CO2 `RHEA:15650`	produces	carbon dioxide `CHEBI:16526`	RHEA:15650 Source assertion: Rhea RHEA:15650 assigns CHEBI:16526 to its products, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/15650']/rh:products; rdf:Description[@rdf:about='http://rdf.rhea-db.org/15649_R']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_15649_compound_4391']; rh:compound/rh:chebi` MetaCyc:RXN0-5222 Source assertion: MetaCyc RXN0-5222 explicitly sets spontaneous=true for carbamate decomposition to ammonium and carbon dioxide. Source location `Reaction[@frameid='RXN0-5222']/spontaneous; left; right`
carbon dioxide `CHEBI:16526`	consumes	CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	RHEA:10750 Source assertion: Rhea RHEA:10750 assigns CHEBI:16526 to its substrates, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/10750']/rh:substrates; rdf:Description[@rdf:about='http://rdf.rhea-db.org/10748_R']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_10748_compound_4391']; rh:compound/rh:chebi`
water `CHEBI:15377`	consumes	CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	RHEA:10750 Source assertion: Rhea RHEA:10750 assigns CHEBI:15377 to its substrates, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/10750']/rh:substrates; rdf:Description[@rdf:about='http://rdf.rhea-db.org/10748_R']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_10748_compound_1283']; rh:compound/rh:chebi`
CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	produces	hydrogencarbonate `CHEBI:17544`	RHEA:10750 Source assertion: Rhea RHEA:10750 assigns CHEBI:17544 to its products, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/10750']/rh:products; rdf:Description[@rdf:about='http://rdf.rhea-db.org/10748_L']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_10748_compound_1123']; rh:compound/rh:chebi`
CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	produces	hydron `CHEBI:15378`	RHEA:10750 Source assertion: Rhea RHEA:10750 assigns CHEBI:15378 to its products, with coefficient 1 in rh:contains1. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/10750']/rh:products; rdf:Description[@rdf:about='http://rdf.rhea-db.org/10748_L']/rh:contains1[@rdf:resource='http://rdf.rhea-db.org/Participant_10748_compound_3249']; rh:compound/rh:chebi`
cyanase `MetaCyc:CYANLY-CPLX`	has_part CynS is the cyanase subunit; catalysis belongs to its native homodecamer. MetaCyc supplies the MG1655 assembly assignment, while the structural study concerns E. coli cyanase.	Cyanate hydratase `UniProtKB:P00816`	MetaCyc:CYANLY-CPLX Source assertion: MetaCyc cyanase CYANLY-CPLX contains ten copies of CYANLY-MONOMER. Source location `Protein[@frameid='CYANLY-CPLX']/component[Protein/@frameid='CYANLY-MONOMER']/coefficient` MetaCyc:CYANLY-MONOMER Source assertion: MetaCyc CYANLY-MONOMER unifies its protein identity with UniProt P00816. Source location `Protein[@frameid='CYANLY-MONOMER']/dblink[dblink-db='UNIPROT',dblink-relationship='unification']/dblink-oid` UniProtKB:P00816 Source assertion: Reviewed UniProt P00816 describes a homodecamer made of five homodimers; its SUBUNIT comment has no inline experimental evidence code. Source location `primaryAccession; comments[commentType='SUBUNIT'].texts` PMID:10801492 The enzyme is functionally active as a homodecamer of 17 kDa subunits Source location `Europe PMC core resultList.result[id='10801492'].abstractText, Background`
carbonic anhydrase 1 `MetaCyc:CARBODEHYDRAT-CPLX`	has_part The graph asserts the CynT component of its own assembly without a fixed oligomer size. It does not adopt the PathBank complex that combines CynT with the distinct Can protein.	Carbonic anhydrase 1 `UniProtKB:P0ABE9`	MetaCyc:CARBODEHYDRAT-CPLX Source assertion: MetaCyc CARBODEHYDRAT-CPLX contains CARBODEHYDRAT-MONOMER. Its coefficient 2 is qualified by the component comment as probably a dimer. Source location `Protein[@frameid='CARBODEHYDRAT-CPLX']/component/Protein; component/coefficient; component/comment` MetaCyc:CARBODEHYDRAT-MONOMER Source assertion: MetaCyc CARBODEHYDRAT-MONOMER unifies with UniProt P0ABE9; its comment describes oligomers of two or four subunits depending on bicarbonate. Source location `Protein[@frameid='CARBODEHYDRAT-MONOMER']/dblink[dblink-db='UNIPROT',dblink-relationship='unification']; comment` UniProtKB:P0ABE9 Source assertion: UniProt describes P0ABE9 as an oligomer, with ECO:0000269 citing PMID:1740425. Source location `comments[commentType='SUBUNIT'].texts` PMID:1740425 behave as an oligomer in solution Source location `Europe PMC core resultList.result[id='1740425'].abstractText`
cyanase `MetaCyc:CYANLY-CPLX`	catalyzes This is the explicit cyanase conversion to carbamate. Bicarbonate is a substrate, not a cofactor; water is not a substrate of this step. The subsequent nonenzymatic decomposition is a separate node.	cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	MetaCyc:CYANLY-CPLX Source assertion: MetaCyc CYANLY-CPLX catalyzes CYANLY-ENZRXN, whose reaction is R524-RXN. Source location `Protein[@frameid='CYANLY-CPLX']/catalyzes/Enzymatic-Reaction[@frameid='CYANLY-ENZRXN']/reaction/Reaction/@frameid` MetaCyc:R524-RXN Source assertion: MetaCyc R524-RXN forms carbamate and carbon dioxide from cyanate, bicarbonate and a proton; its RHEA unification cross-reference is 18490. Source location `Reaction[@frameid='R524-RXN']/left; right; dblink[dblink-db='RHEA',dblink-relationship='unification']/dblink-oid` PMID:3110153 Bicarbonate (not CO2) is the substrate. Source location `Europe PMC core resultList.result[id='3110153'].abstractText` MetaCyc:CYANLY-CPLX Source assertion: The native cyanase assembly CYANLY-CPLX has species TAX-511145, Escherichia coli K-12 MG1655. Source location `Protein[@frameid='CYANLY-CPLX']/species/Organism[@frameid='TAX-511145']`
carbonic anhydrase 1 `MetaCyc:CARBODEHYDRAT-CPLX`	catalyzes CynT accelerates bicarbonate regeneration. Selecting hydration for this pathway does not make carbonic anhydrase irreversible.	CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	MetaCyc:CARBODEHYDRAT-CPLX Source assertion: MetaCyc CARBODEHYDRAT-CPLX catalyzes CARBODEHYDRAT-ENZRXN, whose reaction is RXN0-5224. Source location `Protein[@frameid='CARBODEHYDRAT-CPLX']/catalyzes/Enzymatic-Reaction/reaction/Reaction/@frameid` MetaCyc:RXN0-5224 Source assertion: MetaCyc RXN0-5224 is reversible bicarbonate/proton interconversion with carbon dioxide/water and unifies with bidirectional RHEA:10751. Source location `Reaction[@frameid='RXN0-5224']/reaction-direction; left; right; dblink[dblink-db='RHEA']/dblink-oid` MetaCyc:CYANCAT-PWY Source assertion: The CYANCAT-PWY reaction layout selects RXN0-5224 in R2L direction, consuming carbon dioxide and regenerating bicarbonate. Source location `Pathway[@frameid='CYANCAT-PWY']/reaction-layout[Reaction/@frameid='RXN0-5224']/direction; left-primaries; right-primaries` UniProtKB:P0ABE9 Source assertion: Reviewed UniProt P0ABE9 assigns the RHEA:10748 carbonic-anhydrase reaction and reversible carbon-dioxide hydration, with ECO:0000269 citing PMID:1740425. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction; comments[commentType='FUNCTION'].texts` RHEA:10750 Source assertion: Rhea RHEA:10750 is the right-to-left member of master RHEA:10748, consuming carbon dioxide and water and producing bicarbonate and a proton. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/10748']/rh:directionalReaction; rdf:Description[@rdf:about='http://rdf.rhea-db.org/10750']/rh:substrates and rh:products` MetaCyc:CARBODEHYDRAT-CPLX Source assertion: The native CynT assembly CARBODEHYDRAT-CPLX has species TAX-511145, Escherichia coli K-12 MG1655. Source location `Protein[@frameid='CARBODEHYDRAT-CPLX']/species/Organism[@frameid='TAX-511145']`
Carbonic anhydrase 1 `UniProtKB:P0ABE9`	has_cofactor Zinc binding is supported for the CynT subunit. No bicarbonate cofactor relation is asserted for CynS because bicarbonate participates chemically.	zinc(2+) `CHEBI:29105`	UniProtKB:P0ABE9 Source assertion: UniProt P0ABE9 assigns Zn(2+) CHEBI:29105 and one zinc ion per subunit, with ECO:0000269 citing PMID:1740425. Source location `comments[commentType='COFACTOR'].cofactors; comments[commentType='COFACTOR'].note.texts` PMID:1740425 1 Zn2+/subunit (24 kDa) Source location `Europe PMC core resultList.result[id='1740425'].abstractText`
cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	part_of MG1655 scope comes from native pathway and assembly curation. The current reviewed protein entries cover K-12; the 1993 physiology experiments used K-12 derivatives including HfrR5-derived mutants, not a new direct MG1655 experiment.	`MetaCyc:CYANCAT-PWY`	MetaCyc:CYANCAT-PWY Source assertion: MetaCyc CYANCAT-PWY explicitly includes R524-RXN in its reaction list. Source location `Pathway[@frameid='CYANCAT-PWY']/reaction-list/Reaction[@frameid='R524-RXN']` MetaCyc:R524-RXN Source assertion: MetaCyc R524-RXN has the unification cross-reference RHEA:18490. Source location `Reaction[@frameid='R524-RXN']/dblink[dblink-db='RHEA',dblink-relationship='unification']/dblink-oid` MetaCyc:CYANCAT-PWY Source assertion: MetaCyc CYANCAT-PWY explicitly lists Escherichia coli K-12 MG1655 (TAX-511145) among its species. Source location `Pathway[@frameid='CYANCAT-PWY']/species/Organism[@frameid='TAX-511145']`
carbamate + 2 H(+) => NH4(+) + CO2 `RHEA:15650`	part_of The spontaneous carbamate decay is retained as a pathway step without an enzyme assignment.	`MetaCyc:CYANCAT-PWY`	MetaCyc:CYANCAT-PWY Source assertion: MetaCyc CYANCAT-PWY explicitly includes RXN0-5222 in its reaction list. Source location `Pathway[@frameid='CYANCAT-PWY']/reaction-list/Reaction[@frameid='RXN0-5222']` MetaCyc:RXN0-5222 Source assertion: MetaCyc RXN0-5222 has the unification cross-reference RHEA:15650. Source location `Reaction[@frameid='RXN0-5222']/dblink[dblink-db='RHEA',dblink-relationship='unification']/dblink-oid`
CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	part_of	`MetaCyc:CYANCAT-PWY`	MetaCyc:CYANCAT-PWY Source assertion: MetaCyc CYANCAT-PWY explicitly includes RXN0-5224 in its reaction list. Source location `Pathway[@frameid='CYANCAT-PWY']/reaction-list/Reaction[@frameid='RXN0-5224']` MetaCyc:RXN0-5224 Source assertion: RXN0-5224 unifies with bidirectional RHEA:10751, and CYANCAT-PWY selects its bicarbonate-regenerating direction. Source location `Reaction[@frameid='RXN0-5224']/dblink[dblink-db='RHEA']/dblink-oid; reaction-direction` RHEA:10750 Source assertion: RHEA:10751 and directional RHEA:10750 are both members of master RHEA:10748. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/10748']/rh:bidirectionalReaction and rh:directionalReaction`
cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	provides_input_for The shared carbamate links these steps. The cycle represents available chemical input, not fixed flux or retention of every carbon dioxide molecule.	carbamate + 2 H(+) => NH4(+) + CO2 `RHEA:15650`	MetaCyc:CYANCAT-PWY Source assertion: CYANCAT-PWY names R524-RXN as a predecessor of RXN0-5222; its reaction layouts identify the shared carbamate pool. Source location `Pathway[@frameid='CYANCAT-PWY']/reaction-ordering[Reaction/@frameid='RXN0-5222']/predecessor-reactions/Reaction[@frameid='R524-RXN']; reaction-layout`
carbamate + 2 H(+) => NH4(+) + CO2 `RHEA:15650`	provides_input_for The shared carbon dioxide links these steps. The cycle represents available chemical input, not fixed flux or retention of every carbon dioxide molecule.	CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	MetaCyc:CYANCAT-PWY Source assertion: CYANCAT-PWY names RXN0-5222 as a predecessor of RXN0-5224; its reaction layouts identify the shared carbon dioxide pool. Source location `Pathway[@frameid='CYANCAT-PWY']/reaction-ordering[Reaction/@frameid='RXN0-5224']/predecessor-reactions/Reaction[@frameid='RXN0-5222']; reaction-layout`
CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	provides_input_for The shared bicarbonate links these steps. The cycle represents available chemical input, not fixed flux or retention of every carbon dioxide molecule.	cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	MetaCyc:CYANCAT-PWY Source assertion: CYANCAT-PWY names RXN0-5224 as a predecessor of R524-RXN; its reaction layouts identify the shared bicarbonate pool. Source location `Pathway[@frameid='CYANCAT-PWY']/reaction-ordering[Reaction/@frameid='R524-RXN']/predecessor-reactions/Reaction[@frameid='RXN0-5224']; reaction-layout` PMID:8444806 Source assertion: K-12 cynT deletion mutants retained cyanase but failed to degrade cyanate at 0.03% CO2; 3% CO2 rescued the phenotype, supporting a conditional bicarbonate-regeneration role. Source location `Europe PMC core resultList.result[id='8444806'].abstractText; full article pp.1443,1447-1450`
cyanate + hydrogencarbonate + H(+) => carbamate + CO2 `RHEA:18490`	provides_input_for Carbon dioxide from the first step can also enter the shared carbon-dioxide pool used by CynT. This connection is inferred from the explicit intermediate chemistry and documented recycling role; it is not a separate native ordering claim or quantitative carbon-routing measurement.	CO2 + H2O => hydrogencarbonate + H(+) `RHEA:10750`	RHEA:18490 Source assertion: RHEA:18490 directly produces carbon dioxide CHEBI:16526 alongside carbamate. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/18490']/rh:products; rdf:Description[@rdf:about='http://rdf.rhea-db.org/18489_R']/rh:contains1; rh:compound/rh:chebi` RHEA:10750 Source assertion: RHEA:10750 consumes carbon dioxide CHEBI:16526 and water to regenerate bicarbonate. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/10750']/rh:substrates; rdf:Description[@rdf:about='http://rdf.rhea-db.org/10748_R']/rh:contains1; rh:compound/rh:chebi` UniProtKB:P0ABE9 Source assertion: UniProt assigns CynT the apparent role of hydrating carbon dioxide formed during cyanase-dependent decomposition, limiting cellular bicarbonate depletion (ECO:0000269; PMID:1740425). Source location `comments[commentType='FUNCTION'].texts`
Carbonic anhydrase 1 `UniProtKB:P0ABE9`	located_in	cytoplasm `GO:0005737`	UniProtKB:P0ABE9 Source assertion: UniProt P0ABE9 carries GO:0005737 cytoplasm with IDA:EcoCyc and ECO:0000314 citing PMID:1740425. Source location `uniProtKBCrossReferences[database='GO',id='GO:0005737'].properties and evidences`

References

MetaCyc:CYANCAT-PWY MetaCyc CYANCAT-PWY, cyanate degradation (source version: 22.5; official mirror retrieved 2026-10-10)
MetaCyc:CYANLY-CPLX MetaCyc CYANLY-CPLX, cyanase assembly (source version: 22.5; official mirror retrieved 2026-10-10)
MetaCyc:CARBODEHYDRAT-CPLX MetaCyc CARBODEHYDRAT-CPLX, carbonic anhydrase 1 assembly (source version: 22.5; official mirror retrieved 2026-10-10)
MetaCyc:CYANLY-MONOMER MetaCyc CYANLY-MONOMER, CynS protein (source version: 22.5; official mirror retrieved 2026-10-10)
MetaCyc:CARBODEHYDRAT-MONOMER MetaCyc CARBODEHYDRAT-MONOMER, CynT protein (source version: 22.5; official mirror retrieved 2026-10-10)
MetaCyc:R524-RXN MetaCyc R524-RXN, initial cyanase reaction (source version: 22.5; official mirror retrieved 2026-10-10)
MetaCyc:RXN0-5222 MetaCyc RXN0-5222, spontaneous carbamate decomposition (source version: 22.5; official mirror retrieved 2026-10-10)
MetaCyc:RXN0-5224 MetaCyc RXN0-5224, reversible carbonic anhydrase reaction (source version: 22.5; official mirror retrieved 2026-10-10)
UniProtKB:P00816 Reviewed UniProtKB P00816 (source version: 2026_03; retrieved 2026-10-10)
UniProtKB:P0ABE9 Reviewed UniProtKB P0ABE9 (source version: 2026_03; retrieved 2026-10-10)
RHEA:18490 Rhea 18490 directional reaction (source version: 142 (2026-09-02))
RHEA:15650 Rhea 15650 directional reaction (source version: 142 (2026-09-02))
RHEA:10750 Rhea 10750 directional reaction (source version: 142 (2026-09-02))
PMID:1740425 Carbonic anhydrase in Escherichia coli. A product of the cyn operon. (source version: Europe PMC core metadata retrieved 2026-10-10)
PMID:3110153 Bicarbonate is a recycling substrate for cyanase. (source version: Europe PMC core metadata retrieved 2026-10-10)
PMID:8444806 A physiological role for cyanate-induced carbonic anhydrase in Escherichia coli. (source version: Europe PMC core metadata retrieved 2026-10-10)
PMID:10801492 Structure of cyanase reveals that a novel dimeric and decameric arrangement of subunits is required for formation of the enzyme active site. (source version: Europe PMC core metadata retrieved 2026-10-10)

Curation history

2026-10-10T22:35:05Z codex
- CREATE — Add the CynS and CynT cyanate bicarbonate-recycling pathway
  Ground MetaCyc:CYANCAT-PWY and its CynS/CynT assemblies independently. Retain explicit cyanate-to-carbamate chemistry, spontaneous carbamate decay and bicarbonate regeneration with exact Rhea charge forms and coefficients. Preserve conditional CO2 physiology, MG1655 annotation versus K-12 experiments, oligomer uncertainty, and rejected PathBank mixed-complex and charge assignments. Correct the draft activity category on spontaneous RHEA:15650; no catalyst is invented. Research receipts retain sources, exclusions, duplicate searches and identifier evidence.
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