On the Mechanism of Radiation Induced Reduction of Cytochrome C

Abstract

Kinetic investigations for reduction of cytochrome c in aqueous solution induced by cobalt 60 gamma rays have been carried out. Initial reduction yield of cytochrome c is about 5 as limiting value. The decrease in initial reduction yield in presence of thallous ion as a radical scavenger with ferricytochrome c provides some evidences that OH radicals can contribute to reduction through some possible intermediate. The effects of concentration ratio in ferro-ferricytochrome c and thallotis ion-ferricytochrome c systems on initial reduction yield were investigated. The results can be explained on the basis of some reaction scheme based on the contribution of OH radicals to reduction of ferricytochrome c. The following rate constants were determined by kinetic treatment of the results. kOH+RH2Fe1+ = 5 x lO10M-1 sec-1 kOH+RH2Fe2+ = 4.1 x lO10M-1 sec-1. © 1965, Journal of Radiation Research Editorial Committee. All rights reserved.