Figure 7. Cathepsin activity in human lens epithelial cells (HLEC) after incubation with siramesine. The activity of lysosomal cathepsins was clearly sensitive to siramesine treatment. The diagram shows the dose-dependent increase in proteolytic activity of cathepsin after addition of siramesine 1 h before substrate addition. V_max is shown with mean±SEM where n=8 and significance levels p<0.05 (*), p<0.01 (**) and p<0.001 (***). Three independent experiments were performed with similar results.