HO-1/HMOX1/HSP32: Proteins and Enzymes

Heme Oxygenase (HO), also known as HMOX, is the rate limiting enzyme in the breakdown of heme into Biliverdin, CO, and iron. There are two major isoforms of this enzyme, HO-1 and HO-2. Both have similar enzymatic activity; however, HO-1 is rapidly inducible, while HO-2 is constitutively expressed. Inducers of HO-1 include cell stressors such as oxidative stress, infection, hypoxia, and cytotoxic agents. The reaction products generated by HO-1 activity are biologically active, and the enzyme has a broad range of putative roles. For instance, Biliverdin is an antioxidant with cytoprotective and anti-inflammatory properties, and CO has the potential to suppress inflammation and apoptosis. Because of these activities, HO-1 has received much attention as a therapeutic target for a range of pathological processes.