EC - Phytochromobilin:ferredoxin oxidoreductase

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IntEnz Enzyme Nomenclature


Accepted name:
phytochromobilin:ferredoxin oxidoreductase
Other names:
PΦB synthase
phytochromobilin synthase
PFB synthase
Systematic name:
(3Z)-phytochromobilin:ferredoxin oxidoreductase



Catalyses the two-electron reduction of biliverdin IXα. Can use [2Fe-2S] ferredoxins from a number of sources as acceptor but not the [4Fe-4S] ferredoxin from Clostridium pasteurianum. The isomerization of (3Z)-phytochromobilin to (3E)-phytochromobilin is thought to occur prior to covalent attachment to apophytochrome in the plant cell cytoplasm. Flavodoxins can be used instead of ferredoxin.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0050619
CAS Registry Number: 138263-99-7


  1. Frankenberg, N., Mukougawa, K., Kohchi, T. and Lagarias, J.C.
    Functional genomic analysis of the HY2 family of ferredoxin-dependent bilin reductases from oxygenic photosynthetic organisms.
    Plant Cell 13: 965-978 (2001). [PMID: 11283349]
  2. McDowell, M.T. and Lagarias, J.C.
    Purification and biochemical properties of phytochromobilin synthase from etiolated oat seedlings.
    Plant Physiol. 126: 1546-1554 (2001). [PMID: 11500553]
  3. Terry, M.J., Wahleithner, J.A. and Lagarias, J.C.
    Biosynthesis of the plant photoreceptor phytochrome.
    Arch. Biochem. Biophys. 306: 1-15 (1993). [PMID: 8215388]

[EC created 2002]