Hemeoxygenase (HO) is the rate-limiting enzyme in the catabolism of heme that results in the release of carbon monoxide, iron, and biliverdin. The products of this enzymatic reaction play important biological roles in antioxidant, anti-inflammatory and cytoprotective functions. Hemeoxygenase comprises two isozymes, including the constitutively expressed HO-2 isozyme and the inducible HO-1 isozyme.
