Figure 5.

Gluconeogenesis. Glycolysis and gluconeogenesis share many enzymes; however, there are three irreversible reactions in glycolysis that have to be bypassed so that gluconeogenesis can ensue. The first reaction is the generation of PEP from pyruvate requiring pyruvate carboxylase and PEP carboxykinase. The second reaction is the conversion of fructose 1,6-bisphosphate to fructose 6-phosphate by F-1,6-BPase. The third reaction is the conversion of glucose 6-phosphate to glucose by glucose 6-phosphatase.