title: Biological defense mechanisms. The production by leukocytes of superoxide, a potential bactericidal agent.
abstract: As a highly reactive substance produced in biological systems by the one-electron reduction of oxygen, superoxide (O(2) (-)) seemed a likely candidate as a bactericidal agent in leukocytes. The reduction of cytochrome c, a process in which O(2) (-) may serve as an electron donor, was found to occur when the cytochrome was incubated with leukocytes. O(2) (-) was identified as the agent responsible for the leukocyte-mediated reduction of cytochrome c by the demonstration that the reaction was abolished by superoxide dismutase, an enzyme that destroys O(2) (-), but not by boiled dismutase, albumin, or catalase. Leukocyte O(2) (-) production doubled in the presence of latex particles. The average rate of formation of O(2) (-) in the presence of these particles was 1.03 nmol/10(7) cells per 15 min. This rate, however, is only a lower limit of the true rate of O(2) (-) production, since any O(2) (-) which reacted with constituents other than cytochrome c would have gone undetected. Thus. O(2) (-) is made by leukocytes under circumstances which suggest that it may be involved in bacterial killing.
mesh_terms: D003574:Cytochrome c Group / Q000378:metabolism; D006801:Humans; D007840:Latex / Q000494:pharmacology; D007962:Leukocytes / Q000378:metabolism*; D008863:Microspheres; D010084:Oxidation-Reduction; D010100:Oxygen; D010101:Oxygen Consumption; D013482:Superoxide Dismutase / Q000494:pharmacology
chemical_list: D003574:Cytochrome c Group; D007840:Latex; D013482:Superoxide Dismutase; D010100:Oxygen