Inhibition of the synthesis of ATP during oxidative phosphorylation by oligomycin is thought to be due to which of the following events?
|A||Blocking of the proton gradient between NADH-Q reductase and QH2|
|B||Blocking of the proton gradient between cytochrome c1 and cytochrome c|
|C||Dissociating of cytochrome c from mitochondrial membranes|
|D||Inhibiting of mitochondrial ATPase|
Oligomycin inhibits mitochondrial ATPase and thus prevents phosphorylation of ADP to ATP. It prevents utilization of energy derived from electron transport for the synthesis of ATP Oligomycin has no effect on coupling but blocks mitochondrial phosphorylation so that both oxidation and phosphorylation cease in its presence.
Fig.: Proposed sites of inhibition (-) of the respiratory chain by specific drugs, chemicals, and antibiotics. The sites that appear to support phosphorylation. BAL, dimercaprol. TTFA is an Fe-chelating agent. Complex, NADH: ubiquinone oxidoreductase; complex II, succinate: ubiquinone oxidoreductase; complex Ill, ubiquinol: ferri cytochrome c oxidoreductase; complex IV, ferr cytochrome C: oxygen oxidoreductase.