The Electronic Configurations of Catalases and Peroxidases in their High Oxidation States: A Definitive Assessment
Isr. J. Chem.
The highest oxidation states of catalase and horseradish peroxidase contain 2 oxidizing equivalents more than the resting ferrihemoproteins. Whereas numerous electronic configurations for these primary complexes have been suggested, the most widely accepted formulation is that of an Fe(IV) (S = 1) porphyrin π-cation radical (S = 1/2). The evidence for and against these electronic configurations is summarized and assessed.