TCDD is proposed to decrease the efficiency of ATP formation catalyzed by the
β subunit of F1 within the
F0F1-ATP synthase complex. Respiration would still
depend on ADP, and RCR would remain unchanged. However, ATP/O ratio would
decrease due to uncoupling. Electrons from complex 2 feed into complex 3,
primarily utilizing Q10, from which electrons flow to
Q9 and enter the proton-motive Q cycle. An oxidation state
crossover point exists within complex 3, somewhere between Q10
and Q9.
Abbreviations: AA, antimycin-A; bL and
bH, respectively, low energy and high energy forms of cytochrome
b; ISPs, iron-sulfur proteins; SDH, succinate
dehydrogenase.