Abstract
(Chemical Equation Presented) The dioxygenation of nitric oxide by oxyheme in globin proteins is a major route for NO detoxification in aerobic biological systems. In myoglobin, this reaction is thought to proceed through an iron(III)-bound peroxynitrite before homolytic cleavage of the O?O bond to form an iron(IV)-oxo and NO2 radical followed by recombination and nitrate production. Single turnover experiments at alkaline pH have revealed the presence of a millisecond high-spin heme intermediate. It is widely presumed that this species is an iron(III)-peroxynitrite species, but detailed characterization of the intermediate is lacking. Using resonance Raman spectroscopy and rapid-freeze quench techniques, we identify the millisecond intermediate as an iron(III)-nitrato complex with a symmetric NO2 stretch at 1282 cm?1. Greater time resolution techniques will be required to detect the putative iron(III) peroxynitrite complex.
Original language | English (US) |
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Pages (from-to) | 7234-7235 |
Number of pages | 2 |
Journal | Journal of the American Chemical Society |
Volume | 131 |
Issue number | 21 |
DOIs | |
State | Published - Jun 3 2009 |
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry