GLUCONEOGENESIS INVOLVES GLYCOLYSIS, THE CITRIC ACID CYCLE,
& SOME SPECIAL REACTIONS (Figure 19–1)
Thermodynamic Barriers Prevent a Simple Reversal of Glycolysis
Three nonequilibrium reactions catalyzed by hexoki- nase, phosphofructokinase, and pyruvate kinase prevent simple reversal of glycolysis for glucose synthesis (Chapter 17). They are circumvented as follows:
A. PYRUVATE & PHOSPHOENOLPYRUVATE