Control analysis of the glycolytic flux was carried out in two fast-growth tumor cell types of human and rodent origin (HeLa and AS-30D, respect-ively). Determination of the maximal velocity (Vmax) of the 10 glycolytic enzymes from hexokinase to lactate dehydrogenase revealed that hexokin-ase (153–306 times) and phosphfructokinase-1 (PFK-1) (22–56 times) had higher over-expression in rat AS-30D hepatoma cells than in normal freshly isolated rat hepatocytes.