Fig. 3. Import of inner envelope protein 32 (IEP32) into chloroplasts is independent of protease-sensitive receptors. (A) Intact purified chloroplasts were either treated or not treated with the protease thermolysin for 20 minutes at 4°C. Chloroplasts were repurified on Percoll gradients prior to further use. Efficiency of the proteolytic treatment was controlled by immunoblotting using antisera against the outer envelope localized translocon subunits Toc159, Toc64, Toc34, Toc75III, and Toc75V and the inner envelope translocon subunit Tic110. (B) Chloroplasts from the identical batch as tested in (A) were used for a standard import reaction. All other conditions are as indicated on top of the gel and as described in the legend to Fig. 1A.