Phagocytes and oxidative stress.
Neutrophils and other phagocytes manufacture O(2)(-) (superoxide) by the one-electron reduction of oxygen at the expense of NADPH. Most of the O(2)(-) reacts with itself to form H(2)O(2) (hydrogen peroxide). From these agents a large number of highly reactive microbicidal oxidants are formed, including HOCl (hypochlorous acid), which is produced by the myeloperoxidase-catalyzed oxidation of Cl(-) by H(2)O(2); OH(*) (hydroxyl radical), produced by the reduction of H(2)O(2) by Fe(++) or Cu(+); ONOO(-) (peroxynitrite), formed by the reaction between O(2)(-) and NO(*); and many others. These reactive oxidants are manufactured for the purpose of killing invading microorganisms, but they also inflict damage on nearby tissues, and are thought to be of pathogenic significance in a large number of diseases. Included among these are emphysema, acute respiratory distress syndrome, atherosclerosis, reperfusion injury, malignancy and rheumatoid arthritis.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA.
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Babior
D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D010586:Phagocytes / Q000502:physiology*; D010587:Phagocytosis / Q000502:physiology*; D013481:Superoxides / Q000378:metabolism
D016877:Oxidants; D013481:Superoxides; D009569:Nitric Oxide