Radiolabeled apoferritin protein degradation following inhibition by leupeptin or chloroquine. Cells were labeled with 4 nmol/L ¹²⁵I-apoferritin and chased with 400 nmol/L unlabeled apoferritin. Incubations were performed for 0, 5, 20, and 44 hours. Other experimental conditions were as described in Figs 1 and 2. The intensity of the apoferritin-label was measured by scanning with the phosphor imager of SDS-PAGE performed under reducing conditions. One of 2 experiments with comparable results is shown.