Resonance Raman spectra and biological significance of high-valent iron(IV,V) porphyrins

Extensive research in the past decades has shown that nature relies on high-valent iron (IV,V) porphyrins in a number of enzyme-directed processes of heme proteins. For example, hydroxylation reaction catalyzed by cytochrome P450 involves an iron porphyrin intermediate which contains the oxoferryl moiety (Fe(IV)=O). Liver microsomal cytochrome P450-LM 3,4 is known to catalyze the transfer of a functionalized nitrogen atom intra- as well as inter-molecularly, and the proposed reaction cycle presumably involves a high-valent iron porphyrin intermediate which contains the nitrido-iron moiety(V)EN). This review is focused on the biological significance of these high-valent iron(IV,V) porphyrins and their Fe(IV)=O and Fe(V)equivalent toN stretching vibrations observed in resonance Raman spectra. (C) 2002 Published by Elsevier Science B.V.