Spectroscopic study of the compound ES and the oxoferryl compound II states of cytochrome c peroxidase: comparison with the compound II of horseradish peroxidase

Autor: Ann M. English, Alycen E. Pond, Masanori Sono, John H. Dawson, Grant S. Bruce
Rok vydání: 1998
Předmět:
Zdroj: Inorganica Chimica Acta. :250-255
ISSN: 0020-1693
DOI: 10.1016/s0020-1693(97)06106-9
Popis: Magnetic circular dichroism (MCD) spectroscopic data at −30°C are reported for the oxoferryl compound II state of cytochrome c peroxidase (CcP), which was generated by hydrogen peroxide oxidation of ferrous CcP, in comparison with compound ES (an oxoferryl heme with a protein based-radical) of CcP and compound II (an oxoferryl heme) of horseradish peroxidase (HRP-II). Detailed spectral analyses reveal that the protein-based free radical found in CcP-ES does not significantly perturb the electronic environment of the heme as measured by electronic absorption and MCD spectroscopy. Thus, the spectra of the compounds I and II (oxoferryl) states of CcP are similar. The compound I state of HRP (HRP-1), on the other hand, contains an oxoferryl heme coupled to a porphyrin π-cation radical. As a consequence, HRP-I and HRP-II are well known to have quite distinctive spectra. The similarity of the spectral properties of the two active species of CcP, and the contrasting dissimilarity between the spectral properties of the two active high valent species of HRP, clearly indicates the importance of the protein structure surrounding the heme group in determining the spectral properties of the active species.
Databáze: OpenAIRE
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