title: All hexokinase isoenzymes coexist in rat hepatocytes.
abstract: The cellular distribution of hexokinase isoenzymes, N-acetylglucosamine Kinase and pyruvate kinases in rat liver was studied. Hepatocytes and non-parenchymal cells with high viability and almost no cross-contamination were obtained by perfusion in situ of the liver with collagenase, with the use of an enriched cell-culture medium in all steps of cell isolation. Separation of hexokinase isoenzymes was done by DEAE-cellulose chromatography, and enzyme activities were measured by a specific radioassay. Cytosol from isolated hepatocytes contained high-affinity hexokinases A, B and C, in addition to hexokinase D. The last-mentioned represented about 95% of total glucose-phosphorylating activity. Only hexokinase A was found associated t the particulate fraction. Isolated non-parenchymal cells contained only hexokinases A, B and C. N-Acetylglucosamine kinase was measured with a specific radioassay and was found as a single enzyme form in both hepatocytes and non-parenchymal cells, with higher activities in the former. Pyruvate kinase isoenzyme L was present only in the hepatocytes and isoenzyme K only in the non-parenchymal liver cells, confirming that they are good cellular markers.
mesh_terms: D000818:Animals; D002848:Chromatography, DEAE-Cellulose; D004247:DNA / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism*; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000201:enzymology*; D010770:Phosphotransferases / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor); D011506:Proteins / Q000378:metabolism; D051381:Rats
chemical_list: D007527:Isoenzymes; D011506:Proteins; D004247:DNA; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); D006593:Hexokinase; C018716:N-acetylglucosamine kinase