X-ray Absorption Studies of Myoglobin Peroxide Reveal Functional Differences between Globins and Heme Enzymes

L. Powers, M. Chance, C. Kumar, B. Chance

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X-ray absorption studies of myoglobin peroxide show that although it is not identical with compound I or II of horseradish peroxidase [Chance, B., Powers, L., Ching, Y., Poulos, T., Yamazaki, I., & Paul, K. G. (1984) Arch. Biochem. Biophys. 235, 596–611], it has some structural features in common with both. As seen in compound I, the Fe-O distance is short, but the iron—pyrrole nitrogen distance is contracted with a longer iron—histidine distance like compound II. The iron has a higher oxidation state than Fe3+, suggesting an oxyferryl ion type species. Comparison of the structures of various peroxidase and myoglobin compounds points out systematic differences that may explain the catalytic activity of the π cation radical as well as some of the differences between globins and heme enzymes.

Original languageEnglish (US)
Pages (from-to)1259-1265
Number of pages7
Issue number6
StatePublished - Jan 1 1986
Externally publishedYes


ASJC Scopus subject areas

  • Biochemistry

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