FIGURE 3.

PEX5 inhibits catalase tetramerization. A, ³⁵S-labeled catalase was synthesized in vitro for 55 min (lane 55′) and chased for 4 h in the absence (lane −) or presence of 1 μm of the indicated recombinant proteins. B, same as in A, but using the indicated concentrations of PEX5. C, catalase (lanes 1–3) and a truncated version of it lacking the PTS1 signal (catalaseΔKANL; lanes 4–6) were synthesized for 55 min and chased in the absence (lanes 2 and 5) or presence of 1 μm PEX5 (lanes 3 and 6). D, ³⁵S-labeled catalase was synthesized in vitro for 55 min (lane 1) and chased in the absence (lane 2) or presence of 1 μm of the indicated recombinant proteins (lanes 3–6). ΔC1PEX5 and TPRs, recombinant proteins comprising the N- and C-terminal half of PEX5, respectively. E, same as in A, but using 200 μm of the indicated recombinant proteins. Samples were analyzed by native-PAGE/autoradiography. Note that the gel shown in C was run for 2.5 h. mCat and tCat, monomeric and tetrameric versions of catalase, respectively; mCatΔ and tCatΔ, monomeric and tetrameric forms of catalaseΔKANL, respectively.