Laser Raman spectra of oxidized hydroperoxidases

Resonance Raman spectra of oxidized hydroperoxidases are examined for shifts in the structure-sensitive, anomalously polarized bands; these are found, respectively, at 1576, 1567 and 1570 cm-1 in the high-spin resting enzymes: horse radish peroxidase, horse blood catalase, and cytochrome c peroxidase. In compound II of horse radish peroxidase and horse blood catalase, and in the enzyme-substrate complex of cytochrome c peroxidase, this band appears at 1587-1590 cm-1 and indicates the iron atom is now in-plane with the porphyrin ring. Weak Raman scattering found with horse radish peroxidase I is consistant with a porphyrin eta-cation radical formulation.