Figure 7. Distribution of ⁵⁹Fe^-labeled ferritin throughout different layers of lens fiber cells from noncataractous and cataractous lenses. Lens fiber cell homogenates containing 1500 µg of protein were incubated with ⁵⁹FeCl₃ and separated by 8% SDS-PAGE under nonreducing conditions. The mobility of the assembled ferritin complex was compared to that of 450 kDa canine liver ferritin standards. Incorporation of iron into each layer was expressed as a percent of incorporation into all layers combined. The autoradiograms shown are of a 1-year-old dog’s noncataractous lens and a 10-year-old dog’s lens with an early cataract.