EC 6.6.1.2 - Cobaltochelatase

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IntEnz Enzyme Nomenclature
EC 6.6.1.2

Names

Accepted name:
cobaltochelatase
Other names:
CobN—CobST
CobNST
hydrogenobyrinic acid a,c-diamide cobaltochelatase
Systematic name:
hydrogenobyrinic-acid-a,c-diamide:cobalt cobalt-ligase (ADP-forming)

Reaction

Comments:

This enzyme, which forms part of the aerobic cobalamin biosynthesis pathway, is a type I chelatase, being heterotrimeric and ATP-dependent. It comprises two components, one of which corresponds to CobN and the other is composed of two polypeptides, specified by cobS and cobT in Pseudomonas denitrificans, and named CobST [1]. Hydrogenobyrinic acid is a very poor substrate. ATP can be replaced by dATP or CTP but the reaction proceeds more slowly. CobN exhibits a high affinity for hydrogenobyrinic acid a,c-diamide. The oligomeric protein CobST possesses at least one sulfhydryl group that is essential for ATP-binding. Once the Co2+ is inserted, the next step in the pathway ensures that the cobalt is ligated securely by reducing Co(II) to Co(I). This step is carried out by EC 1.16.8.1, cob(II)yrinic acid a,c-diamide reductase.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0051116
CAS Registry Number: 81295-49-0
UniProtKB/Swiss-Prot:

References

  1. Debussche, L., Couder, M., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F.
    Assay, purification, and characterization of cobaltochelatase, a unique complex enzyme catalyzing cobalt insertion in hydrogenobyrinic acid a,c-diamide during coenzyme B12 biosynthesis in Pseudomonas denitrificans.
    J. Bacteriol. 174: 7445-7451 (1992). [PMID: 1429466]
  2. Warren, M.J., Raux, E., Schubert, H.L. and Escalante-Semerena, J.C.
    The biosynthesis of adenosylcobalamin (vitamin B12).
    Nat. Prod. Rep. 19: 390-412 (2002). [PMID: 12195810]

[EC 6.6.1.2 created 2004]