Haem oxygenase (heme,hydrogen-donor:oxygen oxidoreductase (α-methene-oxidizing, hydroxylating)), E.C. 1.14.99.3, converts heme into biliverdin and carbon monoxide, utilizing NADPH as cofactor.

The existence of a third non-catalytic version of haem oxygenase, HO3, has been proposed, although this has been suggested to be a pseudogene [2]. The chemical tin protoporphyrin IX acts as a haem oxygenase inhibitor in rat liver with an IC₅₀ value of 11 nM [1].

* Key recommended reading is highlighted with an asterisk

* Abraham NG, Kappas A. (2008) Pharmacological and clinical aspects of heme oxygenase. Pharmacol. Rev., 60 (1): 79-127. [PMID:18323402]

Bilban M, Haschemi A, Wegiel B, Chin BY, Wagner O, Otterbein LE. (2008) Heme oxygenase and carbon monoxide initiate homeostatic signaling. J. Mol. Med., 86 (3): 267-79. [PMID:18034222]

Bucolo C, Drago F. (2011) Carbon monoxide and the eye: Implications for glaucoma therapy. Pharmacol. Ther., 130 (2): 191-201. [PMID:21295073]

Chan KH, Ng MK, Stocker R. (2011) Haem oxygenase-1 and cardiovascular disease: mechanisms and therapeutic potential. Clin. Sci., 120 (12): 493-504. [PMID:21355854]

* George EM, Warrington JP, Spradley FT, Palei AC, Granger JP. (2014) The heme oxygenases: important regulators of pregnancy and preeclampsia. Am. J. Physiol. Regul. Integr. Comp. Physiol., 307 (7): R769-77. [PMID:24898840]

* Gozzelino R, Jeney V, Soares MP. (2010) Mechanisms of cell protection by heme oxygenase-1. Annu. Rev. Pharmacol. Toxicol., 50: 323-54. [PMID:20055707]

Khan AA, Quigley JG. (2011) Control of intracellular heme levels: heme transporters and heme oxygenases. Biochim. Biophys. Acta, 1813 (5): 668-82. [PMID:21238504]

Motterlini R, Foresti R. (2014) Heme oxygenase-1 as a target for drug discovery. Antioxid. Redox Signal., 20 (11): 1810-26. [PMID:24180608]

* Poulos TL. (2014) Heme enzyme structure and function. Chem. Rev., 114 (7): 3919-62. [PMID:24400737]

* Rochette L, Cottin Y, Zeller M, Vergely C. (2013) Carbon monoxide: mechanisms of action and potential clinical implications. Pharmacol. Ther., 137 (2): 133-52. [PMID:23026155]

* Wegiel B, Hanto DW, Otterbein LE. (2013) The social network of carbon monoxide in medicine. Trends Mol Med, 19 (1): 3-11. [PMID:23140858]

1. Drummond GS, Kappas A. (1981) Prevention of neonatal hyperbilirubinemia by tin protoporphyrin IX, a potent competitive inhibitor of heme oxidation. Proc. Natl. Acad. Sci. U.S.A., 78 (10): 6466-70. [PMID:6947237]

2. Hayashi S, Omata Y, Sakamoto H, Higashimoto Y, Hara T, Sagara Y, Noguchi M. (2004) Characterization of rat heme oxygenase-3 gene. Implication of processed pseudogenes derived from heme oxygenase-2 gene. Gene, 336 (2): 241-50. [PMID:15246535]

3. Vlahakis JZ, Kinobe RT, Bowers RJ, Brien JF, Nakatsu K, Szarek WA. (2006) Imidazole-dioxolane compounds as isozyme-selective heme oxygenase inhibitors. J. Med. Chem., 49 (14): 4437-41. [PMID:16821802]

Subcommittee members: Andreas Papapetropoulos (Co-chairperson) Drug Discovery & Pharmacology Group Department of Pharmaceutical Chemistry Faculty of Pharmacy University of Athens Athens 15771, Greece Csaba Szabo, MD, PhD (Co-chairperson) Department of Anesthesiology The University of Texas Medical Branch at Galveston 601 Harborside Drive Galveston, TX 77555, USA Timothy R. Billiar Department of Surgery University of Pittsburgh Pittsburgh, PA, USA Giuseppe Cirino Department of Experimental Pharmacology University of Naples-Federico II Via Domenico Montesano 49 80131, Naples, Italy David Fulton Vascular Biology Center Georgia Regents University Sanders Building, CB 3940 Augusta, Georgia, USA Roberto Motterlini Director of Research (DR2) Equipe 12 INSERM U955, Faculty of Medicine University of Paris Est Creteil 94010 Creteil France