Heme-environment of horseradish peroxidase as observed by oxygen-17 superhyperfine interaction in EPR
| Autor: | Gregory R. Schonbaum, Albert S. Mildvan, Raj K. Gupta |
|---|---|
| Rok vydání: | 1979 |
| Předmět: |
inorganic chemicals
Hemeprotein Protein Conformation Iron Biophysics Heme Ligands Photochemistry Biochemistry Horseradish peroxidase law.invention chemistry.chemical_compound law medicine Electron paramagnetic resonance Molecular Biology Horseradish Peroxidase Oxygen-17 biology Ligand Electron Spin Resonance Spectroscopy Cell Biology Solvent Peroxidases chemistry biology.protein Ferric Protein Binding medicine.drug |
| Zdroj: | Biochemical and Biophysical Research Communications. 89:1334-1340 |
| ISSN: | 0006-291X |
| Popis: | The presence of a water ligand on heme-iron in ferric hemoproteins can, in suitable cases, be detected by observing 17O superhyperfine interaction in the EPR spectra of solutions in H217O. Although no significant superhyperfine interaction is detectable in the EPR spectra of horseradish peroxidase itself, benzo-hydroxamic acid, which forms an outersphere complex with the enzyme analogous to an enzyme-peracid transition state, stabilizes an innersphere water ligand on the heme, as indicated by a ∼1.3 gauss Fe3+-17O superhyperfine interaction in the EPR signal at g = 2, in the presence of 34–39% H217O at 8°K. These results indicate that the predominantly pentacoordinate Fe3+ ion in horseradish peroxidase is accessible to the solvent and that it acquires a water or hydroxyl ligand in the presence of benzohydroxamic acid. |
| Databáze: | OpenAIRE |
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