Guanine nucleotides stimulate NADPH oxidase in membranes of human neutrophils.
In the chain of events by which chemotactic peptides stimulate NADPH oxidase-catalyzed superoxide formation in human neutrophils, the involvements of a pertussis toxin-sensitive guanine nucleotide-binding protein (N-protein), mobilization of intracellular calcium and protein kinase C stimulation have been proposed. Superoxide formation was studied in membranes from human neutrophils; NADPH oxidase was stimulated by arachidonic acid in the presence of neutrophil cytosol. Fluoride and stable GTP analogues, such as GTP gamma S and GppNHp, which all activate N-proteins, enhanced NADPH oxidase activity up to 4-fold. GDP beta S inhibited the effect of GTP gamma S. These data suggest that NADPH oxidase is regulated by an N-protein, independent of an elevation of the cytoplasmic calcium concentration.
D002462:Cell Membrane / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D006150:Guanine Nucleotides / Q000494:pharmacology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D009247:NADH, NADPH Oxidoreductases / Q000097:blood*; D019255:NADPH Oxidases; D009504:Neutrophils / Q000201:enzymology*; D013481:Superoxides / Q000097:blood; D013873:Thionucleotides / Q000494:pharmacology
D006150:Guanine Nucleotides; D013873:Thionucleotides; D013481:Superoxides; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases