In aerated water solutions Fe(II)Cytochrome c is slowly oxidized to Fe(III)Cytochrome c by molecular oxygen, from which superoxide anion radicals are produced (kobs = 2.7x10-4 min-1 at 37°C and pH =7.3). The biological importance of this reaction has been evidenced by kinetic investigations in the presence of scavengers. In the presence of superoxide dismutase the oxidation rate is strongly enhanced (kobs = 3x10-3 min –1 at 37°C). Catalase and mannitol reduce the rate constant values by 50% and 25% respectively either in the presence or in absence ofSupeoxide dismutase: differences between rate constants corrispond to the differences in stoichiometric redox ratios indicating that hydrogen peroxide and hydroxyl radicals are formed subsequently to the production of superoxide anion radicals.
PRODUCTION OF REACTIVE OXYGEN-DERIVED SPECIES BY REDOX REACTIONS BETWEEN FE(II)CYTOCHROME-C AND OXYGEN - A KINETIC STUDY
FERRI, Albertino;CALZA, Roberta
1995
Abstract
In aerated water solutions Fe(II)Cytochrome c is slowly oxidized to Fe(III)Cytochrome c by molecular oxygen, from which superoxide anion radicals are produced (kobs = 2.7x10-4 min-1 at 37°C and pH =7.3). The biological importance of this reaction has been evidenced by kinetic investigations in the presence of scavengers. In the presence of superoxide dismutase the oxidation rate is strongly enhanced (kobs = 3x10-3 min –1 at 37°C). Catalase and mannitol reduce the rate constant values by 50% and 25% respectively either in the presence or in absence ofSupeoxide dismutase: differences between rate constants corrispond to the differences in stoichiometric redox ratios indicating that hydrogen peroxide and hydroxyl radicals are formed subsequently to the production of superoxide anion radicals.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
