EC - Heme oxygenase (biliverdin-producing)

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IntEnz Enzyme Nomenclature


Accepted name:
heme oxygenase (biliverdin-producing)
Other names:
ORP33 proteins
haem oxygenase [ambiguous]
heme oxidase [ambiguous]
haem oxidase [ambiguous]
heme oxygenase (decyclizing) [ambiguous]
heme oxygenase [ambiguous]
heme,hydrogen-donor:oxygen oxidoreductase (α-methene-oxidizing, hydroxylating)
Systematic name:
protoheme,hydrogen-donor:oxygen oxidoreductase (α-methene-oxidizing, hydroxylating)



This mammalian enzyme participates in the degradation of heme. The terminal oxygen atoms that are incorporated into the carbonyl groups of pyrrole rings A and B of biliverdin are derived from two separate oxygen molecules [4]. The third oxygen molecule provides the oxygen atom that converts the α-carbon to CO. The enzyme requires NAD(P)H and EC, NADPH--hemoprotein reductase. cf. EC, heme oxygenase (biliverdin-producing, ferredoxin).

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00512
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004392
CAS Registry Number: 9059-22-7
UniProtKB/Swiss-Prot: (55) [show] [UniProt]


  1. Maines, M.D., Ibrahim, N.G. and Kappas, K.
    Solubilization and partial purification of heme oxygenase from rat liver.
    J. Biol. Chem. 252 : 5900-5903 (1977). [PMID: 18477]
  2. Sunderman, F.W., Jr., Downs, J.R., Reid, M.C. and Bibeau, L.M.
    Gas-chromatographic assay for heme oxygenase activity.
    Clin. Chem. 28 : 2026-2032 (1982). [PMID: 6897023]
  3. Yoshida, T., Takahashi, S. and Kikuchi, J.
    Partial purification and reconstitution of the heme oxygenase system from pig spleen microsomes.
    J. Biochem. (Tokyo) 75 : 1187-1191 (1974). [PMID: 4370250]
  4. Noguchi, M., Yoshida, T. and Kikuchi, G.
    Specific requirement of NADPH-cytochrome c reductase for the microsomal heme oxygenase reaction yielding biliverdin IX α.
    FEBS Lett. 98 : 281-284 (1979). [PMID: 105935]
  5. Lad, L., Schuller, D.J., Shimizu, H., Friedman, J., Li, H., Ortiz de Montellano, P.R. and Poulos, T.L.
    Comparison of the heme-free and -bound crystal structures of human heme oxygenase-1.
    J. Biol. Chem. 278 : 7834-7843 (2003). [PMID: 12500973]

[EC created 1972 as EC, modified 2006, transferred 2015 to EC]