Superoxide generation by the electrogenic NADPH oxidase of human neutrophils is limited by the movement of a compensating charge.
The ability of the NADPH oxidase of human neutrophil-derived cytoplasts to generate O2.-anions on the addition of phorbol 12-myristate 13-acetate is severely reduced in the presence of valinomycin and Zn2+ ions. The addition of NH4Cl or carbonyl cyanide m-chlorophenylhydrazone (K+ medium only) to these cytoplasts results in a restoration of O2.- generation. At an elevated pHo CCCP restores a greater rate of O2.- generation. Increasing the concentration of Zn2+ ions reduces the extent of the generation of O2.- on the addition of PMA. The restoration of O2.- generation by NH4Cl or CCCP requires the presence of valinomycin. The restoration of O2.- generation appears to be dependent on the movement of NH4+ ions or the anionic form of the uncoupler across the plasma membrane. The activity of the electrogenic NADPH oxidase of cytoplasts is limited by the movement of an ion to act as a compensator. The NADPH oxidase therefore exhibits respiratory control.
Henderson
L M
LM
Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K.
Chappell
J B
JB
Jones
O T
OT
D000643:Ammonium Chloride / Q000494:pharmacology; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D004579:Electron Transport; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D009247:NADH, NADPH Oxidoreductases / Q000097:blood*; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D013481:Superoxides / Q000097:blood*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology; D015032:Zinc / Q000494:pharmacology
D007477:Ions; D000643:Ammonium Chloride; D013481:Superoxides; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D015032:Zinc; D013755:Tetradecanoylphorbol Acetate