Biomaterial Database

Iron incorporation into apoferritin. The role of apoferritin as a ferroxidase. 1986

G R Bakker, and R F Boyer

Apoferritin catalyzes the oxidation of Fe(II) to Fe(III). Ferroxidase activity is assayed and characterized by coupling the oxidation with the binding of Fe(III) to transferrin. The initial rate of Fe(II) oxidation is dependent on apoferritin and initial Fe(II) concentration but independent of transferrin concentration. The ferroxidase activity is inhibited by Zn(II). Ferritins with varying loads of iron have the same ferroxidase activity level. It is suggested that the described oxidation process represents the initial step of iron deposition in apoferritin. Since transferrin can intercept Fe(III) before it is deposited in apoferritin, active sites for Fe(II) oxidation must be on or near the surface of apoferritin. This finding is contrary to the current view of apoferritin-catalyzed oxidation of Fe(II) which places active sites in the channels to the core or inside the central core.

UI	MeSH Term	Description	Entries
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010088	Oxidoreductases	The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)	Dehydrogenases,Oxidases,Oxidoreductase,Reductases,Dehydrogenase,Oxidase,Reductase
D005290	Ferric Compounds	Inorganic or organic compounds containing trivalent iron.	Compounds, Ferric
D005293	Ferritins	Iron-containing proteins that are widely distributed in animals, plants, and microorganisms. Their major function is to store IRON in a nontoxic bioavailable form. Each ferritin molecule consists of ferric iron in a hollow protein shell (APOFERRITINS) made of 24 subunits of various sequences depending on the species and tissue types.	Basic Isoferritin,Ferritin,Isoferritin,Isoferritin, Basic
D005296	Ferrous Compounds	Inorganic or organic compounds that contain divalent iron.	Compounds, Ferrous
D006736	Horses	Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.	Equus caballus,Equus przewalskii,Horse, Domestic,Domestic Horse,Domestic Horses,Horse,Horses, Domestic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000644	Quaternary Ammonium Compounds	Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN	Quaternary Ammonium Compound,Ammonium Compound, Quaternary,Ammonium Compounds, Quaternary,Compound, Quaternary Ammonium
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia