HPLC profile of the proteolytic fragments of CDB3 generated upon digestion with endoproteinase Asp-N. The phosphorylation and digestion of CDB3 are described in the Materials and Methods. Digested CDB3 (0.5 mg) was applied to a C18 reverse-phase microbore HPLC column (250 × 1 mm) and eluted as described in the Materials and Methods at a flow rate of 50 μL/min. The solid line corresponds to the absorbance at 215 nm, whereas the dashed line represents the radioactivity associated with each major peak. Two radioactive peaks labeled A and B were submitted for sequence analysis, as discussed in the text.