Requires FAD, heme and calcium. When calcium is present, this transmembrane glycoprotein generates H2O2 by transfering electrons from intracellular NAD(P)H to extracellular molecular oxygen. The electron bridge within the enzyme contains one molecule of FAD and probably two heme groups. This flavoprotein is expressed at the apical membrane of thyrocytes, and provides H2O2 for the thyroid peroxidase-catalysed biosynthesis of thyroid hormones.
the phagocyte NADPH oxidase is a multicomponent enzyme complex comprising six proteins, namely p22phox (phox: phagocyte oxidase), gp91phox, p47phox, p67phox, p40phox and the small G-protein Rac1 or Rac2