Inhibition of electron transport of rat liver mitochondria by unnatural (‐)‐antimycin A3

The inhibition of electron transport by unnatural (-)-antimycin A3 was examined with rat liver mitochondria and compared with that of natural (+)-antimycin A3. (-)-Antimycin A3 inhibited respiration about 1/100th as strongly as natural (+)-antimycin A3. (-)-Antimycin A3 binding to the cytochrome bc1 complex did not seem to induce a conformational change in this proteinous complex. The binding site of (-)-antimycin A3 was probably the same as that of (+)-antimycin A3 (at the Qi center). However, the mode of interaction with the Qi center by (-)-antimycin A3 and (+)-antimycin A3 was somewhat different.