Manganese substituted Compound i of cytochrome P450 biomimetics: A comparative reactivity study of MnV-oxo versus MnIV-oxo species

Reza Latifi, Laleh Tahsini, Baharan Karamzadeh, Nasser Safari, Wonwoo Nam, Sam P. De Visser

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Manganese-oxo porphyrins have been well studied as biomimetic models of cytochromes P450 and are known to be able to catalyze substrate hydroxylation reactions. Recent experimental studies [J.Y. Lee, Y.-M. Lee, H. Kotani, W. Nam, S. Fukuzumi, Chem. Commun. (2009) 704] showed that Mn(V)-oxo porphyrins react rapidly with 10-methyl-9,10-dihydroacridine (AcrH2) via a proton-coupled-electron-transfer followed by an electron transfer. In this work, we present a computational study on the reactivity patterns of Mn(V)-oxo and Mn(IV)-oxo with respect to AcrH2. This study shows that although both oxidants are capable of hydroxylating AcrH2, the MnV-oxo species is the more active oxidant. We have generalized these observations with thermodynamic cycles that explain the reaction mechanisms and electron transfer processes. For the MnV-oxo mechanism the reactions proceed with a fast spin state crossing from the ground state singlet to the triplet spin state prior to a hydrogen atom transfer followed by another electron transfer. The present results are fully consistent with previous studies on iron-oxo porphyrins and manganese-oxo porphyrins and shows that the interplay of low lying singlet and triplet spin state surfaces influences the reaction mechanisms and kinetics.

Original languageEnglish
Pages (from-to)4-13
Number of pages10
JournalArchives of Biochemistry and Biophysics
Volume507
Issue number1
DOIs
StatePublished - 1 Mar 2011

Keywords

  • Biomimetic
  • Hydride transfer
  • Hydroxylation
  • Iron-oxo
  • Manganese-oxo
  • Porphyrin

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