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

Abstract
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 cytochromebc1 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.