ABSTRACT
Nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase (NOX) is a membrane-associated, multi-subunit enzyme system that catalyzes the single-electron reduction of molecular oxygen to superoxide. NOX is distinguished by its dedication to the speci£c and deliberate production of reactive oxygen species (ROS), as opposed to other pro-oxidant systems such as mitochondrial electron transport, xanthine oxidases, cyclooxygenases, and monoamine oxidases, which produce free radicals as secondary by-products. NOX was sequentially puriœed and described in a series of publications in the 1970s and 1980s in which NOX was identiœed as the main component of the lymphocytic oxidative burst [1]. These data built upon earlier reports of a “respiratory burst” [2] describing how neutrophils dramatically increased oxygen uptake when phagocytosing bacteria, and indeed, subsequent studies revealed the necessity for oxygen in the killing of engulfed microbes [3]. However, NOX activation does not reect true cellular respiration, and the phrase “extra respiration of phagocytosis” is actually incorrect, as NOX-based oxygen consumption is preserved when mitochondria are poisoned.
