Medical College of Wisconsin
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The effect of melanin on iron associated decomposition of hydrogen peroxide. Free Radic Biol Med 1988;4(5):285-93

Date

01/01/1988

Pubmed ID

2834276

DOI

10.1016/0891-5849(88)90049-4

Scopus ID

2-s2.0-0023884694 (requires institutional sign-in at Scopus site)   127 Citations

Abstract

The effects of melanin on the iron-catalyzed decomposition of hydrogen peroxide to hydroxyl radicals and hydroxyl ions have been studied using electron spin resonance, spin trapping and visible light spectrophotometry. Melanin altered these reactions by several different mechanisms and consequently, depending on conditions, can significantly increase or decrease the yield of reactive products, including hydroxyl radicals. For low concentrations of ferrous ions, melanin decreased the yield of hydroxyl radicals due to binding of ferrous ions by melanin; ferrous ions bound to melanin did not decompose H2O2 efficiently. Melanins increased the rate of hydroxyl radical production if the predominant form of iron was ferric, due to the ability of melanin to reduce ferric to ferrous iron. Hydroxyl radical production in the presence of a strong chelator (e.g. EDTA) and melanin was greater than in the presence of a weak chelator (e.g. ADP) and melanin. Melanin also increased the rate of destruction of the DMPO-OH adduct.

Author List

Pilas B, Sarna T, Kalyanaraman B, Swartz HM

Author

Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adenosine Diphosphate
Cyclic N-Oxides
Edetic Acid
Electron Spin Resonance Spectroscopy
Ferric Compounds
Ferrous Compounds
Hydrogen Peroxide
Hydroxides
Hydroxyl Radical
Iron
Kinetics
Melanins
Oxidation-Reduction
Spectrophotometry
Spin Labels