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Free Radicals in Biochemistry and Medicine

  1. Barry Halliwell

Published Online: 15 SEP 2006

DOI: 10.1002/3527600906.mcb.200300036

Encyclopedia of Molecular Cell Biology and Molecular Medicine

Encyclopedia of Molecular Cell Biology and Molecular Medicine

How to Cite

Halliwell, B. 2006. Free Radicals in Biochemistry and Medicine. Encyclopedia of Molecular Cell Biology and Molecular Medicine. .

Author Information

  1. National University of Singapore, Singapore

Publication History

  1. Published Online: 15 SEP 2006

Abstract

Free radicals and other “reactive” species are constantly generated in vivo, by “accidents of chemistry” and for specific metabolic purposes. The reactivity of different free radicals and “reactive species” varies, but some of them can cause severe damage to biological molecules, especially to DNA, lipids, and proteins. Antioxidant defense systems scavenge reactive species and minimize their formation, but are not 100% effective. Hence, repair systems exist to deal with molecules that have been oxidatively damaged. Damage to DNA by hydroxyl radicals appears to occur in all aerobic cells and might be a significant contributor to the age-dependent development of cancer. Similarly, oxidation of lipids by free radicals contributes to atherosclerosis and related vascular dysfunction, and to the vascular damage in diabetes. Free radicals may play a role in the aging process.

Keywords:

  • Antioxidant;
  • Free Radical;
  • Oxidative Damage;
  • Oxidative Stress;
  • Polyunsaturated Fatty Acid;
  • Reactive Oxygen Species;
  • Reactive Nitrogen Species