THE HEME OXYGENASE SYSTEM:A Regulator of Second Messenger Gases

✍ Scribed by Maines, Mahin D.

• Book ID: 115548378
• Publisher: Annual Reviews
• Year: 1997
• Tongue: English
• Weight: 338 KB
• Volume: 37
• Category: Article
• ISSN: 0362-1642
• DOI: 10.1146/annurev.pharmtox.37.1.517

✦ Synopsis

▪ Abstract  The heme oxygenase (HO) system consists of two forms identified to date: the oxidative stress–inducible protein HO-1 (HSP32) and the constitutive isozyme HO-2. These proteins, which are different gene products, have little in common in primary structure, regulation, or tissue distribution. Both, however, catalyze oxidation of heme to biologically active molecules: iron, a gene regulator; biliverdin, an antioxidant; and carbon monoxide, a heme ligand. Finding the impressive heme-degrading activity of brain led to the suggestion that “HO in brain has functions aside from heme degradation” and to subsequent exploration of carbon monoxide as a promising and potentially significant messenger molecule. There is much parallelism between the biological actions and functions of the CO- and NO-generating systems; and their regulation is intimately linked. This review highlights the current information on molecular and biochemical properties of HO-1 and HO-2 and addresses the possible mechanisms for mutual regulatory interactions between the CO- and NO-generating systems.