[Subcellular distribution of hexokinase in hepatoma and its electrophoretic properties]

In hepatomas of various malignancy contrary to normal and regenerating liver tissue a considerable part of hexokinase (HK) activity was bound with mitochondria. The HK activity, estimated in nuclei, microsomes and apparently in cytoplasma membranes, was due to contamination with mitochondrial fraction. High specific activity of HK in mitochondria of tumors might be responsible for the increased glycolysis, when these organelle preparations were added to the soluble fraction of cells. The HK of tumors was extracted from the preparations by alternative pathways. Reversible binding of some part of the enzyme with mitochondria was regulated by concentration of metabolites (ATP and G6P) similarly to the bound HK from normal tissues (brain, retina). At the same time the other part of unregulated HK activity (isozyme I only) was found in hepatomas to be intercalated into lipoprotein membranes; it was not controlled by metabolites.