ExplorEnz: EC 1.14.99.3

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1.14.99.3

Accepted name:

heme oxygenase

Reaction:

heme + 3 AH₂ + 3 O₂ = biliverdin + Fe²⁺ + CO + 3 A + 3 H₂O

For diagram of the reaction mechanism, click here

Other name(s):

ORP33 proteins; haem oxygenase; heme oxygenase (decyclizing); heme oxidase; haem oxidase

Systematic name:

heme,hydrogen-donor:oxygen oxidoreductase (α-methene-oxidizing, hydroxylating)

Comments:

Requires NAD(P)H and EC 1.6.2.4, NADPH—hemoprotein reductase. 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 central iron is kept in the reduced state by NAD(P)H.

Links to other databases:

BRENDA, EXPASY, KEGG, METACYC, PDB, CAS registry number: 9059-22-7

References:

1.	Maines, M.D., Ibrahim, N.G. and Kappas, K. Solubilization and partial purification of heme oxygenase from rat liver. J. Biol. Chem. 252 (1977) 5900–5903. [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 (1982) 2026–2032. [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 (1974) 1187–1191. [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 (1979) 281–284. [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 (2003) 7834–7843. [PMID: 12500973]

[EC 1.14.99.3 created 1972, modified 2006]