NADPH oxidase complex (phagocyte) (NOX2 (for the main catalytic subunit in humans))

The term **"respiratory burst in phagocytes"** refers not to a single molecule or receptor, but rather to a rapid increase in oxygen consumption by phagocytic immune cells such as neutrophils and macrophages upon activation. This process is mediated by the **NADPH oxidase multi-protein enzyme complex**, which assembles at the plasma or phagosomal membrane following stimulation. The core catalytic component of this system is known as **NOX2** (also called gp91^phox^), which works together with several other subunits including p22^phox^, p47^phox^, p67^phox^, p40^phox^, and small GTPases like Rac1/2[1][4][6][7]. Upon activation—typically triggered by engagement of pattern recognition receptors or Fc/integrin receptors during phagocytosis—the assembled NADPH oxidase transfers electrons from cytosolic NADPH across the membrane onto molecular oxygen within the phagosome. This generates superoxide anion (\(O_2^{\cdot -}\)), which is further converted into hydrogen peroxide (\(H_2O_2\)) and other reactive oxygen species (ROS). These ROS are essential for killing engulfed pathogens but can also contribute to tissue injury if not properly regulated[1][3][5][6]. Defects in any component of this enzyme system result in impaired respiratory burst activity; most notably, mutations affecting NOX2 cause **chronic granulomatous disease**, characterized by recurrent life-threatening infections due to defective microbial killing[4][7]. Conversely, excessive or misdirected ROS production has been implicated in inflammatory diseases. **Note:** "Respiratory burst in phagocytes" describes a cellular process rather than a discrete druggable target; therefore it is not itself a canonical molecular entity suitable for structured drug-target databases. The actual therapeutic target would be one of its components—most commonly referred to as "NADPH oxidase" or specifically "NOX2"[1][4].

Other names

Phagocyte NADPH oxidasePhox complexCytochrome b558 complexNOX2 complex