Ascorbic acid, metal ions and the superoxide radical

Biochem J. 1976 Jun 1;155(3):697-700. doi: 10.1042/bj1550697.

Abstract

1. No evidence could be found for production of the superoxide radical, O2-, during autoxidation of ascorbic acid at alkaline pH values. Indeed, ascorbate may be important in protection against O2- genat-d in vivo. 2. Oxidation of ascorbate at pH 10.2 was stimulated by metal ions. Stimulation by Fe2+ was abolished by superoxide dismutase, probably because of generation of O2-- during reduction of O2 by Fe2+, followed by reaction of O2-- with ascorbate. EDTA changed the mechanism of Fe2+-stimulated ascorbate oxidation. 3. Stimulation of ascorbate oxidation by Cu2+ was also decreased by superoxide dismutase, but this appears to be an artifact, since apoenzyme or bovine serum albumin showed similar effects.

MeSH terms

  • Ascorbic Acid*
  • Edetic Acid
  • Epinephrine
  • Iron
  • Oxidation-Reduction
  • Oxygen*
  • Serum Albumin, Bovine
  • Superoxide Dismutase
  • Superoxides*
  • Zinc

Substances

  • Superoxides
  • Serum Albumin, Bovine
  • Edetic Acid
  • Iron
  • Superoxide Dismutase
  • Zinc
  • Ascorbic Acid
  • Oxygen
  • Epinephrine