Figure 1.

Jac1 of the mitochondrial matrix. (A) Translocation of radiolabeled Jac1 into isolated mitochondria was carried out in the absence (−ΔΨ) or presence of a membrane potential for 7, 15, and 30 min. PK, proteinase K; p, precursor; m, mature. (B) Mitochondria (M) were separated into mitoplasts (MP) and intermembrane space (IMS) fractions. An equivalent portion of mitoplasts was disrupted by addition of deoxycholate detergent (MP + DOC). Equivalent amounts of the fractions were either treated (+PK) or not treated (−PK) with proteinase K. Immunoblot analysis was carried out with antibodies specific for Jac1, cytochrome b₂ (Cyt b₂) as a marker for the intermembrane space, or the matrix protein Mge1 after separation by electrophoresis.