title: Detection of NADPH diaphorase activity associated with human neutrophil NADPH-O2 oxidoreductase activity.
abstract: At approximately equimolar concentrations (approximately 70 microM), and in the presence of excess catalase and superoxide dismutase, DCIP, ferricytochrome c and ferricyanide abstracted 21, 6 and 61%, respectively, of the electron equivalents given up by NADPH to the NADPH-O2 oxidoreductase complex derived from phorbol myristate acetate-stimulated human neutrophils. With a 10-fold increase in ferricyanide, all of the electron equivalents given up by NADPH to the oxidoreductase complex were shunted to ferricyanide concomitant with complete inhibition of NADPH-dependent O2 consumption. These results substantiate the existence of intrinsic diaphorase activity associated with the superoxide generating NADPH-O2 oxidoreductase of human neutrophils.
mesh_terms: D005292:Ferricyanides / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D009247:NADH, NADPH Oxidoreductases / Q000097:blood* / Q000302:isolation & purification; D009252:NADPH Dehydrogenase / Q000097:blood* / Q000302:isolation & purification; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D010101:Oxygen Consumption / Q000187:drug effects
chemical_list: D005292:Ferricyanides; C007931:hexacyanoferrate III; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; C022709:superoxide-forming enzyme; D009252:NADPH Dehydrogenase