Lectures 11-12: The Citric Acid Cycle

Citric acid cycle

Acetyl-CoA (2C) merges w/ oxaloacetate (4C) to form citric acid (6C)

OAA → 2 CO2

Produces 2 CO2, 3 NADH, ATP

Glycolysis connection

Pyruvate is converted into acetyl coenzyme A (CoA)

Feeds into TCA

TCA enzymes

Citrate synthase

Aconitase

Isocitrate dehydrogenase

Multienzyme dehydrogenase complex

Succinyl-CoA synthetase

FAD-dependent succinate dehydrogenase

Fumarase
Malate dehydrogenase

Glucose metabolism products

Glycolysis: 2 pyruvate, 2 NADH, 2 ATP, 2 H2O

TCA: 2 CO2, 3 NADH, 1 GTP, 1 FADH2

Pyruvate → acetyl-CoA: 1 acetyl per glucose, 2 NADH, 2 CO2

Total per glucose molecule: 7 NADH, 2 ATP, 1 GTP, 1 FADH2

Pyruvate oxidation

Cleaves 1 carbon off of pyruvate

Reduces NAD+ → NADH

Results in acetyl-CoA (2C)

Ylid

Molecule w/ adjacent positive & negative charges

Conjugate addition

Attack at an alkene conjugated w/ a carbonyl