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Hydroperoxo-ferric intermediate

SCHEME 4.3 Cytochrome P450 and peroxidase pathways to hydroperoxo-ferric intermediate or Compound 0 (5). Ferric cytochrome P450 (1) is reduced to the ferrous state (2), which can hind dioxygen to form oxy-ferrous complex (3). Reduction of this complex results in the formation of peroxo-ferric complex (4), which is protonated to give hydroperoxo-ferric complex (5). The same hydroperoxo-ferric complex is formed in peroxidases and catalases via reaction with hydrogen peroxide. [Pg.114]

First resonance Raman spectra of hydroperoxo-ferric intermediate in heme proteins, together with EPR and absorption spectra, have been documented in 2003 using horse heart myoglobin.122 Only Fe-0 mode could be measured with Soret excitation... [Pg.126]

Hydroperoxo-ferric intermediate, termed also Compound 0, is the immediate precursor of the main catalytic intermediate Compound I in peroxidase enzymatic cycle. Attempts to study this intermediate directly in reactions of hydrogen peroxide with HRP using fast kinetic methods have been inconclusive, possibly because it is not accumulated in sufficient concentrations.90,91 However, Compound 0 could be prepared and studied by EPR and optical absorption spectroscopy via cryoreduction of... [Pg.127]

Optical absorption spectra of the hydroperoxo-ferric intermediate in HO64 show Soret maximum at 421 nm (5 nm red shifted as compared with 416 nm band for oxy-ferrous HO) and Q-bands at 530 and 557 nm. After annealing at 212-215 K, a new species is formed with Soret band at 406 nm characteristic for the o-meso-hydroxyheme. [Pg.129]

These first detailed characterizations of the peroxo- and hydroperoxo-ferric intermediates in CYPIOIAI [185, 187] provided several important results and enabled further experimental studies with other heme proteins. Clear EPR signatures for the unprotonated peroxo-ferric (gi<2.27) and protonated hydroperoxo-ferric (gi>2.27) intermediates in cytochromes P450... [Pg.82]

The peroxo- and hydroperoxo-ferric intermediates in the mammahan cholesterol side-chain cleaving cytochrome P450 (CYPllAl) has been recently documented [195]. The oxy-complex of CYPllAl with cholesterol bound was radio-lytically reduced at 77 K in 33 % glycerol/phos-phate buffer at pH 7.5. After irradiation the main ciyoreduced intermediate had an EPR signal with gj=2.34 characteristic of a protonated hydroperoxo-ferric complex. However, two minor... [Pg.84]

Davydov R, Perera R, Jin SX, Yang TC, Bryson TA, Sono M, Dawson JH, HofFman BM. 2005. Substrate modulation of the properties and reactivity of the oxy-ferrous and hydroperoxo-ferric intermediates of cytochrome P450cam as shown by cryoreduction EPR/ENDOR spectroscopy. J Am Chem Soc 127(5) 1403-1413. [Pg.418]


See other pages where Hydroperoxo-ferric intermediate is mentioned: [Pg.683]    [Pg.157]    [Pg.119]    [Pg.120]    [Pg.122]    [Pg.122]    [Pg.123]    [Pg.124]    [Pg.129]    [Pg.129]    [Pg.309]    [Pg.153]    [Pg.156]    [Pg.160]    [Pg.81]    [Pg.84]    [Pg.84]    [Pg.85]    [Pg.95]    [Pg.95]    [Pg.105]    [Pg.319]   


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