free radicals

Last reviewed 01/2018

Free radicals are chemicals containing an unpaired electron. They are of immense pathological importance due to their considerable reactivity; they may:

  • attack and modify any cellular chemical:
    • peroxidation of lipids to damage membranes
    • cross-linking of proteins by the formation of disulphide bonds
    • induce mutations in DNA
  • catalyze the formation of more radicals

They are the final common pathway of a number of cellular insults. Aside from the natural tendency for free radicals to decay spontaneously, there are a number of physiological defence mechanisms to prevent free radical propagation.