Fig. 2. The TOM complex is necessary for apocytochrome c translocation. (A) TOM complex-containing proteoliposomes. (B) Liposomes (each corresponding to 300 nmol phospholipid-bound phosphate) were prepared by detergent dilution; anti-apocytochrome c IgG was enclosed by a freeze–thaw technique. Radiolabelled apocytochrome c was added. After 10 min at 25°C, the samples were split and treated with proteinase K in the presence or absence of Triton X-100 (Detergent). Proteins were precipitated with TCA, separated by SDS–PAGE and blotted on to nitrocellulose. Quantitation was by phosphorimager analysis. Immunostaining was performed to visualize Tom40 (A) and the enclosed IgG. a.u., arbitrary units.