Activation of the NADPH oxidase in a cell-free system from human neutrophils stimulated by phorbol myristate acetate.
Kinetics of activation of the NADPH oxidase in a fully soluble cell-free system from phorbol myristate acetate (PMA)-stimulated human neutrophils were investigated. In a cell-free system in which Mg2+ and sodium dodecyl sulfate, an anionic detergent required for the activation of NADPH oxidase are contained, cytosol prepared from PMA-stimulated neutrophils failed to activate PMA-stimulated neutrophil oxidase. However, cytosol prepared from resting (control) neutrophils was capable of activating PMA-stimulated neutrophil oxidase in a cell-free system in which its Km for NADPH was almost similar to that of control neutrophil oxidase. Cytosol from PMA-stimulated neutrophils could not activate control neutrophil oxidase, although it did not contain any inhibitors of NADPH oxidase activation. These results suggest that, in PMA-stimulated neutrophils, cytosolic activation factors may be consumed or exhausted, and that the affinity for NADPH of PMA-stimulated neutrophil oxidase may be the same as that of control neutrophil oxidase.
Umeki
S
S
Department of Medicine, Kawasaki Medical School, Okayama, Japan.
D002474:Cell-Free System; D003600:Cytosol / Q000201:enzymology; D004789:Enzyme Activation; D006801:Humans; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D019255:NADPH Oxidases; D009504:Neutrophils / Q000201:enzymology*; D012967:Sodium Dodecyl Sulfate; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D012967:Sodium Dodecyl Sulfate; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D008274:Magnesium; D013755:Tetradecanoylphorbol Acetate