Hemoglobin and myoglobin are a major source of dietary iron in man. Heme, separated from these hemoproteins by intraluminal proteolysis, is absorbed intact by the intestinal mucosa. The absorbed heme is cleaved in the mucosal cell releasing inorganic iron. Although this mucosal heme-splitting activity initially was ascribed to xanthine oxidase, we investigated the possibility that it is catalyz...

Steiner, Alexandre A., Eduardo Colombari and Luiz G. S. Branco. Carbon monoxide as a novel mediator of the febrile response in the central nervous system. Am. J. Physiol. 277 (Regulatory Integrative Comp. Physiol. 46): R499–R507, 1999.—Heme oxygenase catalyzes the metabolism of heme to biliverdin, free iron, and carbon monoxide (CO), which has been shown to be an important neuromodulatory agent...

A truncated, soluble, and enzymatically active form of human heme oxygenase-2 (DeltaHHO2) was expressed in Escherichia coli. To identify the axial heme ligand of HO-2, His-45 to Ala (DeltaH45A) and His-152 to Ala (DeltaH152A) mutants have been prepared using this expression system. DeltaH45A could form a 1:1 complex with hemin but was completely devoid of the heme degradation activity. A 5-coor...