IUBMB Enzyme Nomenclature


Accepted name: fumarate reductase (quinol)

Reaction: succinate + a quinone = fumarate + a quinol

Other name(s): FRD; menaquinol-fumarate oxidoreductase; succinate dehydrogenase (menaquinone); succinate:menaquinone oxidoreductase; fumarate reductase (menaquinone); complex II (ambiguous)

Systematic name: succinate:quinone oxidoreductase

Comments: The reaction is catalysed in the opposite direction. 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: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Van Hellemond, J.J. and Tielens, A.G. Expression and functional properties of fumarate reductase. Biochem. J. 304 (1994) 321-331. [PMID: 7998964]

2. Iverson, T.M., Luna-Chavez, C., Cecchini, G. and Rees, D.C. Structure of the Escherichia coli fumarate reductase respiratory complex. Science 284 (1999) 1961-1966. [PMID: 10373108]

3. Cecchini, G., Schroder, I., Gunsalus, R.P. and Maklashina, E. Succinate dehydrogenase and fumarate reductase from Escherichia coli. Biochim. Biophys. Acta 1553 (2002) 140-157. [PMID: 11803023]

4. Iverson, T.M., Luna-Chavez, C., Croal, L.R., Cecchini, G. and Rees, D.C. Crystallographic studies of the Escherichia coli quinol-fumarate reductase with inhibitors bound to the quinol-binding site. J. Biol. Chem. 277 (2002) 16124-16130. [PMID: 11850430]

5. van Hellemond, J.J., van der Klei, A., van Weelden, S.W. and Tielens, A.G. Biochemical and evolutionary aspects of anaerobically functioning mitochondria. Philos. Trans. R. Soc. Lond. B Biol. Sci. 358 (2003) 205. [PMID: 12594928]

[EC created 2010, modified 2013]

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