FIGURE 3.

Identification of PPA-binding proteins in BBM. The pass-through fractions from a Sepharose 6B column (lane P), the Me α-Man-eluted fractions from the first PPA column (lane E1), and those from the second PPA column (lane E2) were pooled separately, treated with 1% SDS and 2.5% 2-mercaptoethanol at 100 °C for 5 min, and analyzed by SDS-PAGE using 7.5% polyacrylamide gel (1.5 μg/lane), together with the solubilized BBM (lane BBM). The proteins were detected with SYPRO Ruby protein gel stain. The values on the left indicate the migration positions of the molecular mass markers. The proteins of lane E1 and E2 were identified by LC-MS/MS after trypsin treatment of each gel band, as described under “Experimental Procedures.” On the right, the proteins identified from both E1 and E2 are shown, and those identified from only E1 but not from E2 are shown in parentheses. *, contaminating human keratin bands were detected in E2. VLA-2, integrin very late antigen-2; DPP-IV, dipeptidylpeptidase IV; ACE 2, angiotensin-converting enzyme 2.