NADPH oxidase 2 complex (NOX2 complex)

The NADPH oxidase 2 complex (NOX2 complex) is a multicomponent enzyme system found predominantly in neutrophils. When activated—usually during infection—NOX2 assembles and transfers electrons from NADPH to molecular oxygen, generating superoxide anion, which subsequently forms other reactive oxygen species (ROS) like hydrogen peroxide and hypochlorous acid via the enzyme myeloperoxidase. This rapid "oxidative burst" is critical for killing engulfed pathogens and also contributes to inflammatory signaling and tissue damage when excessive. The process can be triggered by multiple receptor pathways, including Fc gamma receptors and integrins, and is subject to tight spatial and temporal regulation. Dysregulation of NOX2 and its ROS outputs is implicated in chronic inflammatory diseases, sepsis, acute respiratory distress syndrome (such as in COVID-19), and autoimmune conditions.

Other names

phagocyte NADPH oxidasecytochrome b558NOX2 complex

Inhibition of electron transfer (by NOX inhibitors such as DPI or apocynin, prevent ROS generation); Scavenging of ROS (by antioxidants, reduces oxidative damage); Modulation of upstream signaling (blockade of PKC, PI3K, FcγR interactions downregulates NOX2 assembly and activity)