Fig. 3.

NOX2 activity negatively regulates cysteine but not aspartic cathepsin activity in the phagosome. Relative activities of phagosomal proteases were evaluated using cathepsin D/E- and B/L-specific fluorogenic peptides bound to IgG-coupled experimental particles in the presence or absence of NOX2 activity. Phagosomal cathepsin D/E (aspartic cathepsins) (A and B) and cathepsin B/L (cysteine cathepsins) (C and D) activities in resting BMMØs. (A and C) Real-time representative traces. (B and D) Averaged rates between 15 and 40 min postinternalization, relative to DMSO-treated WT samples, from three independent experiments. Error bars represent SEM. P values were determined by ANOVA.