Figure 14.27 illustrates two mechanisms for the transfer of reducing equivalents from the cytosol to the mitochondrion. In order to inhibit both of these shuttle systems (i.e. prevent the transfer of reducing equivalents to the mitochondrion), would rotenone or antimycin A need to be added to the system? Explain your reasoning.
- hcbiochemLv 73 weeks agoFavorite Answer
You see that in the top part of the figure, the electrons are transferred to FAD forming FADH2. That is then oxidized by complex III.
In the lower mechanism, the electrons reduce NAD+ to NADH which is then oxidized by complex I.
So, in order to block both processes, you need an inhibitor the blocks the electron transport system at complex III or later. Rotenone inhibits complex I which would inhibit the second process but not the first. Antimycin A inhibits complex III which would block both of these processes.