Change of human hemopexin isoelectric point upon heme binding

Identification of the Receptor Scavenging Hemopexin- Heme Complexes Running title: Identification of the Hemopexin-Heme Receptor

Binding of heme-hemopexin complexes by soluble HxuA protein allows utilization of this complexed heme by Haemophilus influenzae.

Utilization of heme-hemopexin as a source of heme by Haemophilus influenzae type b is dependent on expression by this bacterium of the 100-kDa HxuA protein, which is both present on the bacterial cell surface and released into the culture supernatant (L. D. Cope, R. Yogev, U. Muller-Eberhard, and E. J. Hansen, J. Bacteriol. 177:2644-2653, 1995). Radioimmunoprecipitation analysis showed that the...

Hemopexin-mediated transport of heme into isolated rat hepatocytes.

Identification of the receptor scavenging hemopexin-heme complexes.

Heme released from heme-binding proteins on internal hemorrhage, hemolysis, myolysis, or other cell damage is highly toxic due to oxidative and proinflammatory effects. Complex formation with hemopexin, the high-affinity heme-binding protein in plasma and cerebrospinal fluid, dampens these effects and is suggested to facilitate cellular heme metabolism. Using a ligand-affinity approach, we puri...

Roles of heme iron-coordinating histidine residues of human hemopexin expressed in baculovirus-infected insect cells.

Hemopexin (Hx), the major heme-binding plasma glycoprotein, scavenges circulating heme and performs an antioxidant function. In the present study, human Hx was expressed in a baculovirus system and its presumed essential His residues were mutated to Thr as a means of investigating their participation in heme binding. The recombinant Hx proteins were purified by sequential chromatography on Con ...