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Absorption of dietary iron in iron salt form (as in most supplements) varies somewhat according to the body's need for iron, and is usually between 10% and 20% of iron intake. Absorption of iron from animal products, and some plant products, is in the form of heme iron, and is more efficient, allowing absorption of from 15% to 35% of intake.
Iron-binding proteins are carrier proteins and metalloproteins that are important in iron metabolism [1] and the immune response. [2] [3] Iron is required for life.Iron-dependent enzymes catalyze a variety of biochemical reactions and can be divided into three broad classes depending on the structure of their active site: non-heme mono-iron, non-heme diiron , or heme centers. [4]
Ferritin genes are highly conserved between species. All vertebrate ferritin genes have three introns and four exons. [8] In human ferritin, introns are present between amino acid residues 14 and 15, 34 and 35, and 82 and 83; in addition, there are one to two hundred untranslated bases at either end of the combined exons. [9]
Since iron is tightly bound to transferrin, cells throughout the body have receptors for transferrin-iron complexes on their surfaces. These receptors engulf and internalize both the protein and the iron attached to it. Once inside, the cell transfers the iron to ferritin, the internal iron storage molecule.
The serum iron pool maintains iron in soluble form, making it more accessible for cells. [3] Oxygen (O 2), nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H 2 S) bind to the iron atom in heme proteins. Once bound to the prosthetic heme groups, these molecules can modulate the activity/function of those hemeproteins, affording ...
Irr, responsive to iron through the status of heme biosynthesis. Has both activator and repressor function. Prevalent in Rhizobium, Bradyrhizobium and many other alphaproteobacteria. [14] The iron dependent repressor family is a functionally similar but non-homologous family of proteins involved in iron homeostasis in prokaryotes. [1]
Metalloprotein is a generic term for a protein that contains a metal ion cofactor. [1] [2] A large proportion of all proteins are part of this category. For instance, at least 1000 human proteins (out of ~20,000) contain zinc-binding protein domains [3] although there may be up to 3000 human zinc metalloproteins. [4]
Crystal structure of iron regulatory protein 1 in complex with ferritin H IRE-RNA, Protein Data Bank entry 2IPY. [1]In molecular biology, the iron response element or iron-responsive element (IRE) is a short conserved stem-loop which is bound by iron response proteins (IRPs, also named IRE-BP or IRBP).