Composition of activated NOX protein family members in membranes.
Individual NOX proteins vary in their requirements for associated p22phox, cytosolic cofactors, and calcium-binding EF hands. In addition, DUOX1 and 2 have an extracellular peroxidase-like (PRX-like) domain and associated transmembrane helix not present in other NOX protein family members. Whereas the phagocyte oxidase (NOX2) and NOX1, 3, and 5 produce O2· extracellularly, only H2O2 is recovered extracellularly from NOX4, DUOX1 or DUOX [see text for details].