Page 584 Glycolysis and TCA cycle: final accounting based on ~2.5 ATP/NADH and 1.5 ATP/FADH2 ~32 ATP/(glucose oxidized to 6CO2) Text – Figures, pg. 584

Free Energies for TCA Reactions note necessity of low (i.e. large negative)  G for citrate synthase to drive preceding malate dehydrogenase reaction. This results in low oxaloacetate concentration. large negative  G steps are points of regulation.* * * *

Figure Regulatory Mechanisms in Pyruvate Dehydrogenase and the TCA Cycle covalent modification of enzymes ex: phosphorylation of pyruvate dehydrogenase (non-covalent) product and feedback inhibition (e.g. by NADH, ATP, citrate) allosteric effectors (ADP/ATP, Ca++)

Figure Points of Regulation in the TCA Cycle inhibition activation Text – Figure 17-16

Figure TCA Cycle intermediates are a major source of molecules for other metabolic pathways note that several of the molecules look like amino acids, except for the absence of an  -amino group Text – Figure 17-17

Page 589 TCA Cycle intermediates are a major source of molecules for other metabolic pathways ex: production of glutamate from  - ketoglutarate

Production of some other amino acids by transamination reactions ex: production of alanine and  -ketoglutarate from glutamate and pyruvate

Page 589 Production of some other amino acids by transamination reactions ex: production of aspartate and pyruvate from oxaloacetate and alanine

Page 590 The depletion of TCA cycle intermediates for use in other pathways must be offset by replenishing (anaplerotic) reactions, including pyruvate carboxylase. Text – Figure, pg. 590