title: Different sensitivity of Zajdela hepatoma mitochondrial ATPase activity to uncouplers in digitonin-treated cells and isolated mitochondria.
abstract: Digitonin-treated Zajdela hepatoma cells and rat hepatocytes devoid of almost all cytosol but retaining intact mitochondria were found to represent a suitable system for direct measurement of mitochondrial ATPase activity. The enzyme activity in digitonin-treated Zajdela hepatoma cells in contrast to that of isolated coupled mitochondria was stimulated by uncouplers. No difference in response of mitochondrial ATPase activity to uncouplers in digitonin-treated hepatocytes and isolated liver mitochondria was found. It is concluded that uncoupler-insensitive mitochondrial ATPase activity does not occur in intact in situ tumor mitochondria but is acquired during the isolation of the organelles.
mesh_terms: D019297:2,4-Dinitrophenol; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D004072:Digitonin / Q000494:pharmacology*; D004140:Dinitrophenols / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D003576:Electron Transport Complex IV / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D014475:Uncoupling Agents / Q000494:pharmacology*
chemical_list: D004140:Dinitrophenols; D014475:Uncoupling Agents; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases; D004072:Digitonin; D019297:2,4-Dinitrophenol