Mechanism of catalysis of Fe(II) oxidation by ferritin H chains

FEBS Lett. 1992 May 11;302(2):108-12. doi: 10.1016/0014-5793(92)80417-f.

Abstract

Recombinant H chain ferritins bearing site-directed amino acid substitutions at their ferroxidase centres have been used to study the mechanism of catalysis of Fe(II) oxidation by this protein. UV-difference spectra have been obtained at various times after the aerobic addition of Fe(II) to the recombinants. These indicate that the first product of Fe(II) oxidation by wild type H chain apoferritin is an Fe(III) mu-oxo-bridged dimer. This suggests that fast oxidation is achieved by 2-electron transfer from two Fe(II) to dioxygen. Modelling of Fe(III) dimer binding to human H chain apoferritin shows a solvent-accessible site, which resembles that of ribonucleotide reductase in its ligands. Substitution of these ligands by other amino acids usually prevents dimer formation and leads to greatly reduced Fe(II) oxidation rates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine
  • Catalysis
  • Ferritins / chemistry
  • Ferritins / genetics
  • Ferritins / metabolism*
  • Ferrous Compounds / chemistry
  • Ferrous Compounds / metabolism*
  • Glutamates
  • Glutamic Acid
  • Humans
  • Macromolecular Substances
  • Models, Molecular
  • Molecular Structure
  • Mutagenesis, Site-Directed
  • Oxidation-Reduction
  • Recombinant Proteins / metabolism
  • Spectrophotometry, Ultraviolet
  • Structure-Activity Relationship

Substances

  • Ferrous Compounds
  • Glutamates
  • Macromolecular Substances
  • Recombinant Proteins
  • Glutamic Acid
  • Ferritins
  • Alanine