Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

heme oxygenase

Name from literature

Heme oxygenase

Pathway from literature

CO generation,degrades heme/production of bilirubin/heme degradation pathway

Pathway from KEGG

Metabolism of Cofactors and Vitamins; Porphyrin and chlorophyll metabolism; map00860


Mouse (10090)

Genome localization

16 B1|16 2.6 cM[15369 ], 8 C1|8 35.0 cM[15368 ],


Requires NAD(P)H and EC, 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 alpha-carbon to CO. The central iron is kept in the reduced state by NAD(P)H.

Rate-limiting Description

"Heme oxygenase (HO)-1 catalyzes the rate-limiting step of heme degradation and plays an important anti-inflammatory role via its enzymatic products carbon monoxide and biliverdin." (18768868)

Regulatory Information

Upstream transcription factor


Regulatory type






transcriptional factor;Elk-3(13713)

"Elk-3 serves as an important repressor of HO-1 gene transcription and contributes to the tight control of HO-1 gene regulation in the setting of inflammatory stimuli" (16456000)

transcriptional factor;NF-kappaB(18033)

"Activation of HO-1 by PMA was mediated via a newly identified kappaB element of the proximal rat HO-1 gene promoter region (-284 to -275). This HO-kappaB element was a nuclear target for the NF-kappaB subunit p65/RelA as determined by nuclear binding assays and transfection experiments with luciferase reporter gene constructs in RAW264.7 monocytes." (18768868)

transcriptional factor;NF-kappaB(18033)

"anti-inflammatory actions mediated by gliotoxin include HO-1 induction and the subsequent blockade of NF-kappaB-dependent signaling pathways in vitro and in vivo" (16804400)

transcriptional factor;"Nrf2(18024),JNK(26419)/c-Jun(16476),AP-1(16476)"

"Nrf2 plays a crucial role in the early activation of HO-1 transcription; tyrosine kinase/JNK/c-Jun plays a key role in the HO-1 upregulation via AP-1" (18404528)

Gene ontology

Gene ontology

GO:0005783 (C) endoplasmic reticulum [P14901, O70252 ];
GO:0004392 (F) heme oxygenase (decyclizing) activity [P14901, O70252 ];
GO:0050896 (P) response to stimulus [P14901 ];
GO:0005506 (F) iron ion binding [P14901, O70252 ];
GO:0006788 (P) heme oxidation [P14901, O70252 ];
GO:0005792 (C) microsome [P14901, O70252 ];
GO:0005634 (C) nucleus [P14901 ];
GO:0055114 (P) oxidation reduction [P14901, O70252 ];

Subcellular localization


endoplasmic reticulum [P14901, O70252 ];

microsome [P14901, O70252 ];



O70252; P14901

Entrez Gene

15368; 15369

  Copyright 2009, Center for Bioinformatics 
  Last Modified: 2009-03-24  
  Design by Zhao Min