NADPH oxidase

The NADPH oxidase (nicotinamide adenine dinucleotide phosphate-oxidase) complex is an enzyme complex

Subunits
It is made up of six subunits. These subunits are:
 * a Rho guanosine triphosphatase (GTPase), usually Rac1 or Rac2 (Rac stands for Rho-related C3 botulinum toxin substrate)
 * Five "phox" units. (Phox stands for phagocytic oxidase.)
 * gp91phox
 * p22phox
 * p40phox
 * p47phox
 * p67phox

Function
The complex is normally latent in neutrophils and is activated to assemble in the membranes during respiratory burst.

It generates superoxide by transferring electrons from NADPH inside the cell across the membrane and coupling these to molecular oxygen to produce the superoxide, which is highly reactive free radical. Superoxide can be produced into phagosomes which contain ingested bacteria and fungi, or it can be produced outside of the cell.

Superoxide is capable of killing bacteria and fungi by its ability to react with other body compounds to generate a large family of reactive oxygen species. These include hydrogen peroxide and hypochlorous acid, the reactive agent in bleach.

Chemical reaction

 * 2 NADPH + O2 ↔ 2 NADP+ + H2O2

Inihibition
NADPH oxidase can be inhibited by apocynin and DPI.Apocynin prevents the assembly of its subunits.