EC - Ascorbate ferrireductase (transmembrane)

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IntEnz Enzyme Nomenclature


Accepted name:
ascorbate ferrireductase (transmembrane)
Other name:
cytochrome b561
Systematic name:
ascorbate:ferric chelate reductase (transmembrane)




A diheme cytochrome that transfers electrons across a single membrane, such as the outer membrane of the enterocyte, or the tonoplast membrane of the plant cell vacuole. Acts on hexacyanoferrate(III) and other ferric chelates.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Flatmark, T., Terland, O.
    Cytochrome b561 of the bovine adrenal chromaffin granules. A high potential b-type cytochrome.
    Biochim. Biophys. Acta 253: 487-491 (1971). [PMID: 4332308]
  2. McKie, A. T., Barrow, D., Latunde-Dada, G. O., Rolfs, A., Sager, G., Mudaly, E., Mudaly, M., Richardson, C., Barlow, D., Bomford, A., Peters, T. J., Raja, K. B., Shirali, S., Hediger, M. A., Farzaneh, F., Simpson, R. J.
    An iron-regulated ferric reductase associated with the absorption of dietary iron.
    Science 291: 1755-1759 (2001). [PMID: 11230685]
  3. Su, D., Asard, H.
    Three mammalian cytochromes b561 are ascorbate-dependent ferrireductases.
    FEBS J. 273: 3722-3734 (2006). [PMID: 16911521]
  4. Berczi, A., Su, D., Asard, H.
    An Arabidopsis cytochrome b561 with trans-membrane ferrireductase capability.
    FEBS Lett. 581: 1505-1508 (2007). [PMID: 17376442]
  5. Wyman, S., Simpson, R. J., McKie, A. T., Sharp, P. A.
    Dcytb (Cybrd1) functions as both a ferric and a cupric reductase in vitro.
    FEBS Lett. 582: 1901-1906 (2008). [PMID: 18498772]
  6. Glanfield, A., McManus, D. P., Smyth, D. J., Lovas, E. M., Loukas, A., Gobert, G. N., Jones, M. K.
    A cytochrome b561 with ferric reductase activity from the parasitic blood fluke, Schistosoma japonicum.
    PLoS Negl Trop Dis 4: e884 (2010). [PMID: 21103361]

[EC created 2011]