Comparison of subcellular activation of the human neutrophil NADPH-oxidase by arachidonic acid, sodium dodecyl sulfate (SDS), and phorbol myristate acetate (PMA).
The phorbol myristate acetate (PMA) stimulation of the human neutrophil NADPH-oxidase has been demonstrated through the activation of protein kinase C (PK-C), using light membrane fractions from nitrogen-cavitated cells. Both arachidonic acid (AA) and sodium dodecyl sulfate (SDS) can also generate an active oxidase in cellfree systems. That the source of O2- with AA and SDS activation is the same NADPH-oxidase as previously studied was confirmed by the similar pH optima and Km values for NADPH as those previously described for the O2- -generating activity harvested from pre-stimulated human neutrophils. In contrast to the stimulation by PMA, however, the stimulation of the NADPH-oxidase by AA and SDS does not appear to require protein kinase C activation: the action of AA and SDS is independent of the addition of PK-C cofactors to the system, and the inhibitor of PK-C activity, H-7, had no effect on the stimulation by AA or SDS. AA and SDS activation are comparable, but the level of NADPH-oxidase expression is sixfold greater with each of these agents than that obtained with a reconstituted PK-C system. The basis of this difference in oxidase expression is unclear, but these findings suggest strongly that although activated PK-C is capable of stimulating a dormant NADPH-oxidase in a cellfree system, this is not the sole pathway for oxidase activation.
D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D019255:NADPH Oxidases; D009504:Neutrophils / Q000201:enzymology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013347:Subcellular Fractions / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D001095:Arachidonic Acids; D016718:Arachidonic Acid; D012967:Sodium Dodecyl Sulfate; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate