Figure 2. Separation of 65-year-old human lens proteins using 15% polyacrylamide gel by SDS–PAGE analysis and identification of excised bands by MALDI-TOF mass spectrometry. A: SDS–PAGE image of proteins in three lenticular regions with Coomassie Blue R250 staining showing mostly LMW species. Samples from the outer and inner cortices were repeated in the last two lanes on the right side of the gel. B: Expanded image seen in A. Boxes outline the bands excised for mass spectrometric analysis and crystallin identifications of excised bands were based on MALDI-TOF data.