Characterization of rat liver mitochondria depleted of inner membrane components by chloramphenicol treatment of regenerating rat liver.

The maximal decline of adenosine triphosphate phosphohydrolase (ATPase; EC 3.6.1.3) in mitochondria from regenerating rat liver on treatment with chloramphenicol occurs between 48 and 72 h after partial hepatectomy. The depleted mitochondria are well coupled, exhibiting a respiratory control ratio of about 7 with succinate. These mitochondria are fully sensitive to rutamycin for the inhibition of succinate state 3 respiration. In frozen-thawed mitochondria there is a 60% reduction in ATPase activity, and of this remaining ATPase activity only 50% is sensitive to rutamycin. The titers for release of succinate state 4 respiration and ATPase activity by 5-Cl, 3-tert-butyl, 2′-Cl, 4′-NO₂-salicylanilide are decreased, and the efficiency of the uncoupler is increased. The antimycin titer for inhibition of succinate state 3 respiration is decreased. In all cases where a decrease in activity or titer was observed it is about the same (50%), suggesting inhibition at a common site for these parameters.