Superoxide dismutase isoenzymes in bovine and human milk

Carl L Keen, Bo Lönnerdal, Theodore N. Stein, Lucille S. Hurley

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The presence of superoxide dismutase in bovine and human milk was investigated by ultrafiltration, gel filtration, and isoelectric focusing. Conclusive evidence for the presence of this enzyme in both milks is presented. The molecular weight of the enzyme was estimated by gel filtration on Sephadex G-100 to be 30,000, which is consistent with reported values for the copper, zinc form of superoxide dismutase. In addition, enzyme activity was inhibited by cyanide, thus eliminating the possibility that the enzyme was present in the manganese form. Several isoenzymes were detected by isoelectric focusing in polyacrylamide gel, and the isoenzyme pattern in bovine milk was the same as that found for bovine plasma, suggesting that milk superoxide dismutase originates from plasma. It may be that the presence of copper, zinc superoxide dismutase in milk is important for the maintenance of its oxidative stability.

Original languageEnglish (US)
Pages (from-to)221-227
Number of pages7
JournalBiological Trace Element Research
Issue number3
StatePublished - Sep 1980


  • copper, zinc superoxide dismutase, in milk
  • gel filtration, of superoxide dismutase
  • isoelectric focusing, of superoxide dismutase
  • milk, superoxide dismutase in bovine and human
  • plasma, and superoxide dismutase
  • Superoxide dismutase, in bovine and human milk
  • ultrafiltration, of superoxide dismutase

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry, medical
  • Inorganic Chemistry
  • Clinical Biochemistry
  • Biochemistry


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