Anti-P40PHOX antibodies enable researchers to detect and measure the P40PHOX antigen in biological samples. This target is a reported synonym of the NCF4 gene, which encodes neutrophil cytosolic factor 4. This protein is a known component of the NADPH-oxidase, a multicomponent enzyme system responsible for the oxidative burst in which electrons are transported from NADPH to molecular oxygen, generating reactive oxidant intermediates. The human version of P40PHOX has a canonical amino acid length of 339 residues and a protein mass of 39 kilodaltons, although 2 isoforms have been identified. It is reported to be localized in the membrane and cytoplasm of cells and notably expressed in the rectum, lymph node, lung, colon, and bone marrow. Other names for this target antigen include CGD3 and NCF. ELISA, Western Blot, and Immunohistochemistry are common applications for P40PHOX antibodies.