NCF1 is a 47 kDa cytosolic subunit of neutrophil NADPH oxidase. This protein is essential for activation of the NADPH oxidase complex, which is essential for superoxide production. It cooperates with NCF2 to form a core association in the complex, interacting with NCF4, CYBB and CYBA. Mutations in the NCF1 gene have been associated with chronic granulomatous disease.