The Utility of Superoxide Dismutase in Studying Free Radical Reactions

These results indicate that of these electron carriers only the reduced forms of menadione and of the flavins preferentially reduce O2 to the superoxide radical in the presence of cytochrome c

J.M. McCord; I. Fridovich

2021

Scholarcy highlights

  • TPN reductase of spinach or by chicken liver xanthine dehydrogenase is markedly augmented by a variety of electron carriers
  • When cytochrome c reduction was mediated by these same electron carriers in the absence of molecular oxygen, superoxide dismutase was without effect
  • When cytochrome c reduction was mediated by N-methylphenazinium methosulfate, methylene blue, or 2,6-dichlorobenzenone indophenol, superoxide dismutase was without effect whether or not oxygen was present
  • These results indicate that of these electron carriers only the reduced forms of menadione and of the flavins preferentially reduce O2 to the superoxide radical in the presence of cytochrome c
  • It is clear that superoxide dismutase is a potent inhibitor of cytochrome c reduction in these systems but that 70% inhibition is the maximum which could be achieved
  • G by Ferredoxin-TPN Reductase-The rate of reduction of cytochrome c by ferredoxin-TPN reductase plus TPNH was extremely slow but was powerfully accelerated by a variety of electron carriers, all of which were ineffective in the absence of the enzyme
  • In this case 0; was detected by its ability to oxidize epinephrine to adrenochrome

Need more features? Save interactive summary cards to your Scholarcy Library.