Biological Defense Mechanisms. THE PRODUCTION BY LEUKOCYTES OF SUPEROXIDE, A POTENTIAL BACTERICIDAL AGENT

A C T As a highly reactive substance produced in biological systems by the one-electron reduction of oxygen, superoxide (02-) seemed a likely candidate as a bactericidal agent in leukocytes. The reduction of cy- tochrome c, a process in which 02may serve as an electron donor, was found to occur when the cytochrome was incubated with leukocytes. 02- 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 02-, but not by boiled dismutase, albumin, or catalase.