Biogenesis of Mitochondrial Membranes: Biochemical and Morphological Evidence of Two Protein-Synthesizing Systems 1

Summary

The in vivo incorporation of ³H-leucine into inner and outer mitochondrial membrane has been investigated in rats during enhanced liver mitochondriogenesis.

Administration of cycloheximide for 3 days (1.5 mg/kg body weight, intraperitoneally) caused a 34% inhibitin of incorporation into outer membrane, as compared to controls, but was without effect on the incorporation into inner membrane. Chloramphenicol administered orally for 3 days (2.5%) inhibited incorporation into inner membrane and to a lesser degree into outer membrane.

The results reported support the conclusion that biosynthesis of outer mitochondrial membrane is dependent on protein synthesis localized in the endoplasmic reticulum, whereas the system associated with synthesis of the inner membrane appears to be localized within the mitochondrion.