EC - Fumarate reductase (quinol)

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IntEnz Enzyme Nomenclature


Accepted name:
fumarate reductase (quinol)
Other names:
menaquinol-fumarate oxidoreductase
succinate dehydrogenase (menaquinone)
succinate:menaquinone oxidoreductase
fumarate reductase (menaquinone)
complex II [ambiguous]
Systematic name:
succinate:quinone oxidoreductase



The enzyme, which is found in anaerobic and facultative organisms such as bacteria, parasitic helminthes, and lower marine organisms, utilizes low potential quinols, such as menaquinol and rhodoquinol, to reduce fumarate as the final step of an anaerobic respiratory chain. The enzyme is known as complex II of the electron transfer chain, similarly to EC, succinate dehydrogenase (quinone), to which it is closely related.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0102040
UniProtKB/Swiss-Prot: (14) [show] [UniProt]


  1. Van Hellemond, J. J., Tielens, A. G.
    Expression and functional properties of fumarate reductase.
    Biochem. J. 304 ( Pt 2): 321-331 (1994). [PMID: 7998964]
  2. Iverson, T. M., Luna-Chavez, C., Cecchini, G., Rees, D. C.
    Structure of the Escherichia coli fumarate reductase respiratory complex.
    Science 284: 1961-1966 (1999). [PMID: 10373108]
  3. Cecchini, G., Schroder, I., Gunsalus, R. P., Maklashina, E.
    Succinate dehydrogenase and fumarate reductase from Escherichia coli.
    Biochim. Biophys. Acta 1553: 140-157 (2002). [PMID: 11803023]
  4. Iverson, T. M., Luna-Chavez, C., Croal, L. R., Cecchini, G., Rees, D. C.
    Crystallographic studies of the Escherichia coli quinol-fumarate reductase with inhibitors bound to the quinol-binding site.
    J. Biol. Chem. 277: 16124-16130 (2002). [PMID: 11850430]
  5. van Hellemond, J. J., van der Klei, A., van Weelden, S. W., Tielens, A. G.
    Biochemical and evolutionary aspects of anaerobically functioning mitochondria.
    Philos. Trans. R. Soc. Lond., B, Biol. Sci. 358: 205-213 (2003). [PMID: 12594928]

[EC created 2010, modified 2013]