Electron-nuclear double resonance of horseradish peroxidase compound I. Detection of the porphyrin pi-cation radical. Academic Article uri icon


  • Electron-nuclear double resonance spectra of horseradish peroxidase Compound I exhibit resonances from 14N and beta-protons, and most probably alpha-protons as well. The measurements prove that the oxyferryl iron of this enzymic intermediate is spin-coupled to a porphyrin radical. Comparison of experimentally obtained average pi-electron spin densities with theoretical predictions for a 4-fold symmetric porphyrin pi-cation radical is supportive of a 2A2u assignment for the radical's electronic state.

published proceedings

  • J Biol Chem

author list (cited authors)

  • Roberts, J. E., Hoffman, B. M., Rutter, R., & Hager, L. P

citation count

  • 131

complete list of authors

  • Roberts, JE||Hoffman, BM||Rutter, R||Hager, LP

publication date

  • March 1981