TCA Pathway Flashcards
Provides majority of ATP for energy
Gluconeogenesis from skeletons of AA
Building blocks for AA and heme (succinyl CoA)
TCA
Final common pathway for the aerobic oxidation of ALL nutrients: CARBOHYDRATES, LIPID, PROTEIN
Tricarboxylic acid pathway/ KREBS CYCLE/ Citric Acid Cycle
Where does TCA pathway occurs?
In ALL cells with mitochondria
Mitochondrial matrix
Except: Succinate dehydrogenase (inner membrane)
What is the substrate?
Acetyl CoA
What are the products?
CO2, GTP, NADH and FADH2
What is the rate-limiting?
Reaction: isocitrate ➡️ a-ketoglutarate
Enzyme: isocitrate dehydrogenase
Acetyl CoA + Oxaloacetate ➡️ CITRATE
Enzyme: citrate synthase
Citrate ➡️ ISOCITRATE (isomerization)
Enzyme: Aconitase
Inhibitor: Fluoroacetate (rat poison)
Isocitrate ➡️ a-KETOGLUTARATE
This is the rate limiting step
Enzyme: Isocitrate dehydrogenase
Produces: CO2 and NADH
a-ketoglutarate dehydrogenase ➡️ SUCCINYL CoA
Enzyme: a-ketoglutarate dehydrogenase
Co-enzymes: similar to pyruvate dehydrogenase
Produces: Co2, NADH
Inhibitor: Arsenite
Succinyl CoA ➡️ SUCCINATE
Enzyme: Succinate thiokinase
Produces: GTP by substrate level phosphorylation
Succinate ➡️ FUMARATE
Enzyme: Succinate dehydrogenase
Produces: FADH2
Fumarate ➡️ MALATE
Enzyme: Fumarase (Fumarate hydratase)
Malate ➡️ OXALOACETATE
Enzyme: Malate dehydrogenase
Produces: NADH
Divers acetyl CoA to the cytoplasm for fatty acid synthesis via a citrate shuttle
Citrate
