Question

Considering that all other dehydrogenases of glycolysis and the TCA cycle use NADH as the electron donor, why does succinate dehydrogenase, a component of the TCA cycle and the electron-transfer chain, use FAD as the electron acceptor from succinate, rather than $\mathrm{NAD}^{+}$ ? Note that there are two justifications for the choice of FAD here one based on energetics and one based on the mechanism of electron transfer for FAD versus $\mathrm{NAD}^{+}$.

Name: Considering that all other dehydrogenases of glycolysis and the TCA cycle use NADH as the electron donor, why does succinate dehydrogenase, a component of the TCA cycle and the electron-transfer chain, use FAD as the electron acceptor from succinate, rather than NAD^+ ? Note that there are two justifications for the choice of FAD here one based on energetics and one based on the mechanism of electron transfer for FAD versus NAD^+.
Uploaded: 2024-06-13T21:19:37-08:00
Duration: 3 min 5 s
Channel: George Bennett

          Considering that all other dehydrogenases of glycolysis and the TCA cycle use NADH as the electron donor, why does succinate dehydrogenase, a component of the TCA cycle and the electron-transfer chain, use FAD as the electron acceptor from succinate, rather than $\mathrm{NAD}^{+}$ ? Note that there are two justifications for the choice of FAD here one based on energetics and one based on the mechanism of electron transfer for FAD versus $\mathrm{NAD}^{+}$.

Added by David E.

Organic Chemistry

Janice Gorzynski Smith 4th Edition

Instant Answer

Solved by Expert George Bennett

06/13/2024

Step 1

The oxidation of succinate to fumarate by succinate dehydrogenase releases two electrons. These electrons are used to reduce FAD to FADH2. FADH2 has a lower reduction potential than NADH, meaning that it carries less energy. This is advantageous because the Show more…

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Considering that all other dehydrogenases of glycolysis and the TCA cycle use NADH as the electron donor, why does succinate dehydrogenase, a component of the TCA cycle and the electron-transfer chain, use FAD as the electron acceptor from succinate, rather than $\mathrm{NAD}^{+}$ ? Note that there are two justifications for the choice of FAD here one based on energetics and one based on the mechanism of electron transfer for FAD versus $\mathrm{NAD}^{+}$.