FIGURE 1.

SDS-PAGE analysis of tag-free iPLAβ after cation-exchange chromatography. The tag was removed from iPLAβ-StrepIII by selective proteolysis with Factor Xa, and the reaction mixture was submitted to cation-exchange chromatography as described under “Experimental Procedures.” A, right column fraction containing all PLA activity was analyzed by SDS-PAGE, and the gel was stained with Coomassie Blue. B, left column shows the PLA-containing fraction stained with anti-iPLAβ antibody (1:100 dilution). The left column in A and the right column in B show the marker protein and molecular weights.