ELECTRON-SPIN-RESONANCE STUDIES ON THE ACTIVE INTERMEDIATE IN THE ENZYMATIC REDUCTION OF THE FE-BLEOMYCIN COMPLEX

  • 1 May 1987
    • journal article
    • research article
    • Vol. 14  (5) , 879-887
Abstract
The spin trapping method was applied to elucidate the active intermediate during the enzymatic reduction of Fe(III)-bleomycin in the presence of NADPH-cytochrome P-450 reductase and O2. Although the hydroxyl adducts to spin traps were observed, the adduct formation was not inhibited by catalase nor by SOD. Furthermore, in Tris-HC1 buffer, no Tris adduct to the spin trap was observed. The results lead to the conclusion that there is no participation of free OH radical in the reactive intermediate in this reduction system. Effect of phosphate buffer on the reactivity of Fe(II)-bleomycin and spin state of Fe(III)-bleomycin were discussed.