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ENZYME

ENZYME entry: EC 4.99.1.3

PURL: https://purl.expasy.org/enzyme/EC/4.99.1.3
Accepted Name
sirohydrochlorin cobaltochelatase
Alternative Name(s)
anaerobic cobalt chelatase
cobaltochelatase
Reaction catalysed
  • Co-sirohydrochlorin + 2 H(+) = sirohydrochlorin + Co(2+)
  • Co-precorrin-2 + 3 H(+) = precorrin-2 + Co(2+)
Comment(s)
  • This enzyme, which forms part of the anaerobic (early cobalt insertion) cobalamin biosynthesis pathway, is a type II chelatase.
  • It is ATP-independent and exists as either a monomer (CbiX) or a homodimer (CibK).
  • CbiK from Salmonella enterica uses precorrin-2 as the substrate to yield cobalt-precorrin-2.
  • The enzyme contains two histidines at the active site that are thought to be involved in the deprotonation of the tetrapyrrole substrate as well as in metal binding.
  • CbiX from Bacillus megaterium inserts cobalt at the level of sirohydrochlorin (factor-II) rather than precorrin-2.
  • See EC 6.6.1.2 for the cobaltochelatase that participates in the aerobic cobalamin biosynthesis pathway.
Cross-references
Rhea expert-curated reactions4.99.1.3
ExplorEnz4.99.1.3
IUBMB Enzyme Nomenclature4.99.1.3
UniProtKB/Swiss-Prot
Q72CB8, CBIKC_NITV2Q72EC8, CBIKP_NITV2Q05592, CBIK_SALTY
O29537, CBIX_ARCFUQ9HQM3, CBIX_HALSAO87690, CBIX_PRIMG
C3NGG2, CBIX_SACI1C3MR05, CBIX_SACI2C3MZ53, CBIX_SACI3
C3MWZ3, CBIX_SACI4C4KID1, CBIX_SACI6C3N773, CBIX_SACI7
Q980A7, CBIX_SACS2Q4JAI2, CBIX_SULACQ975N6, CBIX_SULTO
Q55451, CBIX_SYNY3A6UWT5, CFBA_META3Q8TJZ5, CFBA_METAC
P61816, CFBA_METBFQ12X56, CFBA_METBUQ58380, CFBA_METJA
Q8TY77, CFBA_METKAQ8PZH6, CFBA_METMAP61819, CFBA_METMP
O27448, CFBA_METTH
BRENDA4.99.1.3
MetaCyc4.99.1.3
KEGG Ligand Database for Enzyme Nomenclature4.99.1.3
EC2PDB4.99.1.3
MEDLINEFind literature relating to 4.99.1.3

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