Neutrophil cytosol factor 2 is the 67-kilodalton cytosolic subunit of the multi-protein complex known as NADPH oxidase found in neutrophils. This oxidase produces a burst of superoxide which is delivered to the lumen of the neutrophil phagosome. Mutations in this gene, as well as in other NADPH oxidase subunits, can result in chronic granulomatous disease.

Using neutrophils from a patient with p67-deficient CGD, Okamura et al. (1990) confirmed that the p67 protein functions in the respiratory burst mediated by NADPH oxidase and that p67 may be complexed to p47-phox (NCF1) while it participates in oxidase activation.