ABSTRACT
NADPH oxidase is a short redox chain composed of two intramembrane cytochrome components: a hemopolypeptide of about 22 kD with a halfredox potential of -245 mV and a flavoprotein component of about 91 kD. The affinity of NADPH oxidase for anions is evident in the inhibition of its activity by a variety of nucleotides and anions like fluoride, pyrophosphate, and citrate. The constitutive production of the 22-kD hemopolypeptide of NADPH oxidase in such a diverse group of cells could be linked to its being a very sensitive membrane-bound detector of heat, oxidative, and radiation stressors. NADPH oxidase and nitric oxide synthase, which are both found in neutrophils and macrophages, are activated in parallel by gamma-interferon and lipopolysaccharide or tumor necrosis factor. The NADPH oxidase of the ovum is cyanide insensitive, requires calcium and magnesium ions and adenosine triphosphate followed by a 60-s lag before hydrogen peroxide production.
