FIGURE 8.

A, the proteasomal MBP degradation was tested in the presence of increasing concentrations of MgCl₂, as indicated. The percentage of protein remaining was calculated as the ratio of protein at the points indicated, relative to the protein without 26S proteasome. The proteasome was active across the range of MgCl₂ titration. B, acetylation (left) and deimination (right) of MBP inhibits its 26S-mediated proteolysis. Shown is an RP-HPLC profile (i) and native PAGE (ii) of the modified and non-modified MBP. iii, hydrolysis of the nonmodified and PAD, peptidylarginine deiminase modified MBP by the 26S proteasome, as indicated. bovMBP, bovine MBP.