The circadian rhythm of the liver maintains glucose homeostasis, and disruption of this rhythm is associated with type 2 diabetes. Feeding is one factor that sets the circadian clock in peripheral tissues, but relatively little is known about the role of specific dietary components in that regard. We assessed the effects of dietary iron on circadian gluconeogenesis. Dietary iron affects circadi...

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 ...

In the deoxy ferrous state of histidine-ligated heme proteins, the iron-histidine band (νFe-His) has been assigned as a stretching mode that involves a two-body motion involving the iron and histidine combined with a minor amount of heme doming. An analogous Raman band, νFe-L has been observed in the proximal cavity mutant of H93G myoglobin where the Raman band of a series of nonnative axial li...

For many pathogenic bacteria like Pseudomonas aeruginosa heme is an essential source of iron. After uptake, the heme molecule is degraded by heme oxygenases to yield iron, carbon monoxide, and biliverdin. The heme oxygenase PigA is only induced under iron-limiting conditions and produces the unusual biliverdin isomers IXbeta and IXdelta. The gene for a second putative heme oxygenase in P. aerug...

In vertebrates, most iron is present as heme or is chelated by proteins. Thus, Gram-positive pathogens such as Staphylococcus aureus have evolved an iron-regulated surface determinant (Isd) system that transports heme across thick cell walls into the cytoplasm. Recent studies have demonstrated that heme is rapidly transferred between the NEAr Transporter (NEAT) domains of the Isd system, despit...

The porphin requirements of the Hemophilus organisms have been studied. Organisms of the parainfluenzae group show quantitative differences in their ability to synthesize heme. The ability of the parainfluenzae organisms to grow appears to depend on the rate with which they synthesize heme and in part at least on the properties of the medium to protect the heme from peroxidative breakdown. Quan...

Heme is a compound consisting of an iron (Fe) atom bound to pyrrole ring forming protoporphyrin IX (PPIX). Protoporphyrin combines with protein-forming hemoprotein that plays essential role in oxygen-binding and transport as well the process energy production mitochondria. Some cancer cells have more heme biosynthesis than normal cells, which thought be linked cell growth. Inhibition some leads...

BACKGROUND Results of cross-sectional studies suggest that in healthy people, iron absorption adapts to meet physiologic needs and stabilize iron stores, but this has not been adequately tested in longitudinal studies. OBJECTIVE We tested whether heme- and nonheme-iron absorption decrease in response to increased iron intake and whether iron stores reach a steady state. DESIGN In a randomiz...

The transport of heme across membranes is critical for iron absorption, the formation of hemoglobin and other hemoproteins, and iron recycling in macrophages. However, the identity of heme transport proteins has been elusive. In this issue of the JCI, Chiabrando et al. reveal that an isoform of the feline leukemia virus subgroup C receptor (FLVCR1) exports heme from the mitochondria and is crit...

Synthetic modeling studies of non-heme iron proteins continue to contribute to our understanding of the mechanism of these proteins. Recently, mononuclear Fe(IV)=O complexes have been prepared and characterized to model the same species that are proposed to be the reactive intermediates in reactions involving mononuclear non-heme iron proteins. Generation of such species for the oxidation of or...