Figure 10. Ethambutol (EMB) induced release of cathepsin D from lysosome in RPE50 cells. RPE50 cells were treated with 0.8 mM EMB for 0, 1, and 3 h. A western blot of cathepsin D in the crude lysosomal fraction was performed. A nonspecific band in the Ponceau S stained blot was included as an internal control. The relative ratios of the band intensity of cathepsin D versus the nonspecific band, taking the ratio at time zero as 1.0, are shown . The results were an average of two repeated experiments with a coefficient of variation (CV) of 6.0%–8.0%.