Cytochrome P-450-butyl peroxide complex detected by ESR.
ESR measurements were performed for the reaction systems composed of t- or n-butylhydroperoxide and cytochrome P-450 (UT-2), purified from rat liver microsomes. On addition of n-butylhydroperoxide to the P-450 at pH 7.4, ESR signal due to a ferric low-spin species (g1 = 2.29, g2 = 2.24 and g3 = 1.96) was recorded. The observed g-parameters agreed well with those of a model thiolate-heme-iron(III)-peroxide complex, Fe(III)TPP(-S-TGE) (-OO-t-butyl) (g1 = 2.285, g2 = 2.198 and g3 = 1.959). In terms of the g-parameters, the new P-450 complex was concluded to be a P-450-butyl peroxide adduct, in which a butyl peroxide anion ligates at the sixth position of heme iron(III).
Department of Chemistry, Faculty of Science, Ehime University, Matsuyama, Japan.
K
K
Tajima
T
T
Edo
K
K
Ishizu
S
S
Imaoka
Y
Y
Funae
S
S
Oka
H
H
Sakurai
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000302:isolation & purification / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology*; D016877:Oxidants / Q000378:metabolism; D010545:Peroxides / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D013113:Spin Labels; D020122:tert-Butylhydroperoxide
D016877:Oxidants; D010545:Peroxides; D013113:Spin Labels; C080013:n-butylhydroperoxide; D003577:Cytochrome P-450 Enzyme System; D020122:tert-Butylhydroperoxide