Enzyme Pathway controlled Gene involved Isoform expressed in tumor cells Isoform expressed in normal cells
Hexokinase Glycolysis Hexokinase (HK) Hexokinase II (HK II) Hexokinase I, III, IV (HK I, III and IV)
Phosphofructokinase-2 (PFK-2) Glycolysis 6-phospho-2-kinase/fructose2, 6-biphosphatase (PFKFB1-4) 6-phospho-2-kinase/fructose2, 6-biphosphatase (PFKFB3 and PFKFB4) 6-phospho-2-kinase/fructose2, 6-biphosphatase (PFKFB1 and PFKFB2)
Pyruvate Kinase Glycolysis Pyruvate Kinase M1 and M2 (PKM1 and PKM2) Pyruvate Kinase M2 (PKM2) Pyruvate Kinase M1 (PKM1)
Pyruvate dehydrogenase kinase (PDK) Between Glycolysis and TCA Cycle Pyruvate dehydrogenase kinase (PDK 1-4) Pyruvate dehydrogenase kinase (PDK)1 Pyruvate dehydrogenase kinase (PDK2, PDK3 and PDK4)
Glutaminase Glutamine metabolism Glutaminase 1 and Glutaminase 2 Glutaminase 2 Glutaminase 1
Table 2: Metabolic enzymes, the pathway they regulate and their isoforms expression in normal and tumor cells.