BACKGROUND Nitrosylated and non-nitrosylated heme iron from red processed and nonprocessed meat have been associated with increased colorectal carcinogenesis. Mechanisms include oxidative processes. It has been hypothesized that dietary antioxidants could counteract the effects of heme iron. We investigated the relationships between heme iron intake and the risk of colorectal adenomas, and a po...

Circadian rhythms in energy metabolism and behavior have been examined at the molecular level with the identification of key clock genes that synchronize the endogenous rhythms in metabolism to external cues (zeitgebers), primarily day–night cycle and activity. These rhythms are temporally orchestrated and rigorously regulated by the central oscillators located in the suprachiasmatic nuclei and...

Heme is an iron-containing porphyrin ring that serves as a prosthetic group in proteins that function in diverse metabolic pathways. Heme is also a major source of bioavailable iron in the human diet. While the synthesis of heme has been well-characterized, the pathways for heme trafficking remain poorly understood. It is likely that heme transport across membranes is highly regulated, as free ...

Oxygen activation in all heme enzymes requires the formation of high oxidation states iron, usually referred to as ferryl heme. There are two known intermediates: Compound I and II. The nature heme—and whether it is an FeIV=O or FeIV-OH species—is important for controlling reactivity across groups enzymes. most recent evidence indicates that unprotonated species. For II, not unambiguously estab...

BACKGROUND MicroRNA-210 (miR-210) increases in hypoxia and regulates mitochondrial respiration through modulation of iron-sulfur cluster assembly proteins (ISCU1/2), a protein that is involved in Fe/S cluster synthesis. However, it is not known how miR-210 affects cellular iron levels or production of heme, another iron containing molecule that is also needed for cellular and mitochondrial func...

The Corynebacterium diphtheriae hmuO gene encodes a heme oxygenase that is involved in the utilization of heme as an iron source. Transcription of hmuO is activated by heme or hemoglobin and repressed by iron and DtxR. Previous studies with Escherichia coli showed that heme-dependent transcriptional activation of an hmuO promoter-lacZ fusion was dependent on the cloned C. diphtheriae chrA and c...

The dog behaves like man in his ability to utilize dietary hemoglobin iron and, therefore, is an excellent model in which to study the mechanisms of absorption. Heme is taken up intact into the epithelial cell of the small intestine but the iron appears in the plasma in a nonheme form. A substance is present in mucosal homogenates which is capable of releasing iron from a hemoglobin substrate i...

Developing erythrocytes take up exceptionally large amounts of iron, which must be transferred to mitochondria for incorporation into heme. This massive iron flux must be precisely controlled to permit the coordinated synthesis of heme and hemoglobin while avoiding the toxic effects of chemically reactive iron. In cultured animal cells, iron chaperones poly rC-binding protein 1 (PCBP1) and PCBP...

Virtually all aerobic organisms synthesize heme, an iron protoporphyrin complex that functions as an oxygen transporter and electron carrier in multiple enzymes and mitochondrial respiratory chain complexes. Heme is synthesized by a highly conserved multistep process, beginning with the condensation of glycine and succinyl-CoA by ALA synthase (ALAS) to form 5-aminolevulinic acid, and continuing...

The gene annotated BAB2_1150 in the Brucella abortus 2308 genome sequence is predicted to encode a homolog of the well-characterized heme transporter ShuA of Shigella dysenteriae and accordingly has been given the designation bhuA (Brucella heme utilization). Phenotypic analysis of an isogenic bhuA mutant derived from B. abortus 2308 verified that there is a link between BhuA and the ability of...