The effects of N-ethylmaleimide on extracellularly and intracellularly generated chemiluminescence in neutrophils indicate that the rate of deactivation of NADPH-oxidase is higher when the oxidase system is localized on the plasma membrane than when it is localized on the phagosomal membrane.
Sustained generation of reactive oxygen metabolites following respiratory burst activation in neutrophils is a result of continued replenishment of a pool of active NADPH-oxidase. The sulphydryl-modifying reagent N-ethylmaleimide (NEM) has been shown to be without effect on the turnover of activated NADPH-oxidase but to inhibit the replenishment of active oxidase molecules (Akard et al., 1988). NEM was thus used to determine the rate of deactivation of extracellularly and intracellularly generated chemiluminescence in human neutrophils. We have shown that deactivation is more rapid when activation leads to a release of oxygen metabolites (extracellular chemiluminescence) than when the metabolites are generated intracellularly. The results indicate that the rate of deactivation of NADPH-oxidase is higher when the oxidase system is localized on the plasma membrane than when it is localized on the phagosomal membrane.
Dahlgren
C
C
Department of Medical Microbiology, University of Linköping, Sweden.
Sundqvist
T
T
D000328:Adult; D002462:Cell Membrane / Q000378:metabolism; D005033:Ethylmaleimide / Q000494:pharmacology*; D005110:Extracellular Space / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism; D008163:Luminescent Measurements; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010588:Phagosomes / Q000378:metabolism
D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D005033:Ethylmaleimide; D010100:Oxygen