title: Structural and functional analyses of chicken liver ferritin.
abstract: Characterization of ferritins from different species has provided insight into iron regulation mechanisms and evolutionary relationships. Here, we examined chicken liver ferritin, which comprises only H subunit and has 14.8 µg of Fe/100 µg of protein. The chicken H subunit apo homopolymer showed the same iron uptake rate as bovine H subunit homopolymer expressed with a baculovirus expression system (0.31 and 0.28 mmol of Fe/min per micromole of protein for chicken and bovine H subunit, respectively). Chicken H subunit apo homopolymer showed a significantly higher biotinylated hemin-binding activity than liver holoferritin. Although bovine spleen apoferritin, which has an L (liver or light):H (heart or heavy) subunit ratio of 1:1, also shows a significantly higher biotinylated hemin-binding activity than its holoferritin, these biotinylated hemin-binding activities were markedly lower than those of both chicken holo- and apoferritins. Binding of chicken holo- and apoferritin with biotinylated hemin was strongly inhibited by hemin but not iron-free hemin, protoporphyrin IX, or Zn-protoporphyrin. These findings demonstrate that chicken ferritin comprises only an H subunit, possesses ferroxidase activity as in mammalian ferritin H subunits, and binds heme more strongly than mammalian ferritins.
authors.affiliation: School of Veterinary Medicine, Kitasato University, Aomori 034-8628, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Yuge
authors.forename: A
authors.initials: A
authors.lastname: Uda
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshikawa
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Orino
mesh_terms: D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D005293:Ferritins / Q000378:metabolism*; D006427:Hemin / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008970:Molecular Weight
chemical_list: D006427:Hemin; D005293:Ferritins; D007501:Iron