Duodenal cytochrome b (DCYTB) in iron metabolism: an update on function and regulation

Nutrients. 2015 Mar 31;7(4):2274-96. doi: 10.3390/nu7042274.

Abstract

Iron and ascorbate are vital cellular constituents in mammalian systems. The bulk-requirement for iron is during erythropoiesis leading to the generation of hemoglobin-containing erythrocytes. Additionally; both iron and ascorbate are required as co-factors in numerous metabolic reactions. Iron homeostasis is controlled at the level of uptake; rather than excretion. Accumulating evidence strongly suggests that in addition to the known ability of dietary ascorbate to enhance non-heme iron absorption in the gut; ascorbate regulates iron homeostasis. The involvement of ascorbate in dietary iron absorption extends beyond the direct chemical reduction of non-heme iron by dietary ascorbate. Among other activities; intra-enterocyte ascorbate appears to be involved in the provision of electrons to a family of trans-membrane redox enzymes; namely those of the cytochrome b561 class. These hemoproteins oxidize a pool of ascorbate on one side of the membrane in order to reduce an electron acceptor (e.g., non-heme iron) on the opposite side of the membrane. One member of this family; duodenal cytochrome b (DCYTB); may play an important role in ascorbate-dependent reduction of non-heme iron in the gut prior to uptake by ferrous-iron transporters. This review discusses the emerging relationship between cellular iron homeostasis; the emergent "IRP1-HIF2α axis"; DCYTB and ascorbate in relation to iron metabolism.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Ascorbic Acid / administration & dosage
  • Ascorbic Acid / metabolism
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Cytochrome b Group / metabolism
  • Cytochromes b / metabolism*
  • Disease Models, Animal
  • Duodenum / drug effects*
  • Duodenum / metabolism
  • Erythropoiesis / drug effects
  • Humans
  • Iron Regulatory Protein 1 / genetics
  • Iron Regulatory Protein 1 / metabolism
  • Iron, Dietary / administration & dosage
  • Iron, Dietary / pharmacokinetics*

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Cytochrome b Group
  • Iron, Dietary
  • cytochrome b561
  • endothelial PAS domain-containing protein 1
  • Cytochromes b
  • ACO1 protein, human
  • Iron Regulatory Protein 1
  • Ascorbic Acid