citric acid cycle
Through a series of oxidation-reduction reactions results in the oxidation of an acetyl group, two molecules of Co2 and the harvesting of high energy electrons-- completes the breakdown of glucose
Where is the citric acid cycle located?
mitochondria
What is the overall purpose of the citric acid cycle?
Catabolic pathway in which compounds derived from the breakdown of carbohydrates, fats and proteins are oxidized to CO2
What are the starting compounds of the citric acid cycle?
Acetyl CoA
3 NAD +
FAD
GDP
Pi
2H2O
What are the ending compounds of the citric acid cycle?
CoA
3 NADH
FADH2
2 CO2
GTP
2 H+
Oxaloacetate
How do the control points of the CAC control it?
The control points within the cycle regulate metabolic flux
What are the regulatory points of the CAC?
Citrate Synthase
Isocitrate dehydrogenase
Alpha-Ketoglutarate
How is citrate synthase regulated?
Inhibited by ATP, Citrate, NADH, and succinyl CoA
Stimulated by ADP
How is isocitrate dehydrogenase regulated?
Inhibited by NADH and ATP
Stimulated by ADP and Ca2+
How is Alpha-Ketoglutarate regulated?
Inhibited by NADH, Succinyl-CoA, and ATP
Stimulated by AMP and Ca2+
What branch points are present in the CAC?
Complex III connects to electron transport chain
Are there diseases associated with the CAC?
Intermediates link to signals in immunity and cancer
Cancer: Succinylation as a post-transcriptional modification
Pro-inflammatory effects in Macrophages: Generates ROS, activates Hypoxia inducible factor (HIF-1alpha)
What type of pathway is the CAC?
CAC is an amphibolic pathway that serves both anabolic and catabolic processes
how is energy held in the CAC
Most of the energy created from the oxidation is held temporarily in NADH and FADH2 ? those electrons are later transferred to O2 and the energy of electron flow is trapped in ATP
How many enzymatic reactions are in the CAC?
Eight
Synthases
catalyze condensation reactions without the participation of nucleotide triphosphate
Synthetases
condensation reactions with the participation of nucleotide triphosphates
The CAC is a site of both Anaplertoic reactions (up) and catapoleric reactions (down)
Anaplertoic reactions replenish the pool of intermediates in the TCA cycle
catapoleric reactions dispose of TCA cycle intermediates
Why is the CAC a furnace?
oxidation of Acetyl CoA to CO2