Involved in heme iron utilization (PubMed:19091096, PubMed:21030596). Catalyzes the degradation of heme to biliverdin, with the release of iron and carbon monoxide (PubMed:19091096, PubMed:21030596). Release of iron from heme may play a crucial role in the pathogenicity of H.pylori (PubMed:19091096). 3 AH2 + 3 H(+) + heme b + 3 O2 = 3 A + biliverdin delta + CO + Fe(2+) + 3 H2O Homodimer. Down-regulated by iron. Deletion mutant cannot utilize heme iron for normal growth. Belongs to the heme oxygenase HugZ/HutZ family.