Schematic representation of glucose metabolism. 1: Hexokinase/glucokinase, 2: Glycogen synthase, 3: Phosphorylase, 4: Phosphofructokinase, 5: Pyruvate kinase, 6: Pyruvate carboxylase, 7: Phosphoenolpyruvate carboxykinase, 8: Fructose-1,6-biphosphatase, 9: Glucose-6-phosphatase.