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.
|Original language||English (US)|
|Number of pages||4|
|Journal||Journal of Biological Chemistry|
|State||Published - Mar 10 1981|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology