TCA Cycle: Succinate Dehydrogenase Flashcards
What is the only TCA Cycle enzyme that is membrane-bound?
succinate dehydrogenase
Where is succinate dehydrogenase located?
It is bound to the inner membrane of the mitochondria.
What reaction does succinate dehydrogenase catalyze?
Stereo-specific dehydrogenation of succinate to fumarate
What inhibits succinate dehydrogenase? What type of inhibitor is it?
malonate; it is a competitive inhibitor, it is a structural analog of succinate
What is unique about succinate dehydrogenase containing FAD?
FAD is covalently linked to the enzyme; most often FAD is not covalently linked to an enzyme.
What types of reactions does FAD tend to do?
Oxidation of alkanes to alkenes
What types of reactions does NAD+ tend to do?
Oxidation of alcohols to ketones.
On which membrane of the mitochondria does all of the metabolic action take place?
Inner membrane
Which oxidation reactions are more exergonic, those involving FAD or those using NAD+?
NAD+
What are the products of the step of the TCA Cycle involving succinate dehydrogenase?
fumarate and FADH2
What must happen to the FADH2 produced in this step before the next catalytic cycle? How is this accomplished?
It must be reoxidized; 2 electrons are passed into electron transport
How do the 2 electrons from FADH2 get to the electron transport chain?
They are funneled there directly by succinate dehydrogenase (this is possible because the enzyme is bound to the inner-mitochondrial membrane.
How is succinyl dehydrogenase regenerated for the next cycle?
By funneling 2 electrons from FADH2 into the electron transport chain.
