Gluconeogenesis Consumes ATP

The organization of glycolysis and gluconeogenesis as a series of connected metabolic pools makes it possible for most of the same enzymes to function in both directions. Only the reactions connecting the metabolic pools require different enzymes and a coupling to the ATP-ADP system to make them thermodynamically feasible in the direction of gluconeogenesis. 

In three of the reactions connecting the pools we find a big drop in free energy in the glycolytic direction (see table 12.1). Clearly if cells are to conduct these reactions in the reverse direction, ATP must be pumped into the system and different enzymes will be required. 

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Gluconeogenesis Consumes ATP Conversion of Pyruvate to Phosphoenolpyruvate Requires Two High Energy Phosphates Conversion of Phosphoenolpyruvate to Fructose-1,6-bisphosphate Uses the Same Enzymes as Glycolysis... 

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