Heme oxygenase, an essential enzyme in heme catabolism,
cleaves heme to form biliverdin, which is subsequently converted to
bilirubin by biliverdin reductase, and carbon monoxide, a putative
neurotransmitter. Heme oxygenase activity is induced by its
substrate heme and by various nonheme substances. Heme oxygenase
occurs as 2 isozymes, an inducible heme oxygenase-1 and a
constitutive heme oxygenase-2. HMOX1 and HMOX2 belong to the heme
oxygenase family. Alternative splice variants encoding the same
protein have been identified at this locus.
