Crotonyl-CoA carboxylase/reductase

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Crotonyl-CoA carboxylase/reductase
Crotonyl-CoA carboxylase/reductase tetramer, Streptomyces sp. NRRL 2288
EC no.
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum

Crotonyl-CoA carboxylase/reductase (EC, CCR, crotonyl-CoA reductase (carboxylating)) is an enzyme with systematic name (2S)-ethylmalonyl-CoA:NADP+ oxidoreductase (decarboxylating).[1][2] This enzyme catalyses the following chemical reaction

(2S)-ethylmalonyl-CoA + NADP+ (E)-but-2-enoyl-CoA + CO2 + NADPH + H+

The reaction is catalysed in the reverse direction. This reaction is a part of the ethylmalonyl-CoA pathway (EMC).

Normally, the Glyoxylate cycle is present in microorganisms to assimilate acetate. However, in microorganisms that do not have a Glyoxylate cycle, CCR is important for its role in an alternative pathway to assimilate acetate.

There are various CCR homologues and in S. tsukubaensis' genome the CCR homologues ccr1 and allR were identified and recognized to be a part of two separate metabolic pathways.[3] The homologue ccr1 is involved in the EMC pathway, whereas the homologue allR is involved in biosynthesis of immunosuppressants FK506/FK520.


  1. ^ Erb TJ, Berg IA, Brecht V, Müller M, Fuchs G, Alber BE (June 2007). "Synthesis of C5-dicarboxylic acids from C2-units involving crotonyl-CoA carboxylase/reductase: the ethylmalonyl-CoA pathway". Proceedings of the National Academy of Sciences of the United States of America. 104 (25): 10631–6. Bibcode:2007PNAS..10410631E. doi:10.1073/pnas.0702791104. PMC 1965564. PMID 17548827.
  2. ^ Erb TJ, Brecht V, Fuchs G, Müller M, Alber BE (June 2009). "Carboxylation mechanism and stereochemistry of crotonyl-CoA carboxylase/reductase, a carboxylating enoyl-thioester reductase". Proceedings of the National Academy of Sciences of the United States of America. 106 (22): 8871–6. Bibcode:2009PNAS..106.8871E. doi:10.1073/pnas.0903939106. PMC 2689996. PMID 19458256.
  3. ^ Blažič, M., Kosec, G., Baebler, Š., Gruden, K., & Petković, H. (2015). Roles of the crotonyl-CoA carboxylase/reductase homologues in acetate assimilation and biosynthesis of immunosuppressant FK506 in Streptomyces tsukubaensis. Microbial cell factories, 14, 164.

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