title: Monovalent carboxylic ionophores inhibit transport of carbamoyl-phosphate synthetase I into mitochondria in Reuber hepatoma H-35 cells and cause accumulation of enzyme precursor.
abstract: Transport of the precursor for carbamoyl-phosphate synthetase I into mitochondria in Reuber hepatoma H-35 cells was inhibited by adding monensin or nigericin to the culture medium at a concentration of 0.5 microM, and the enzyme precursor accumulated, mainly in the cytosolic fraction. Accumulated precursor was degraded slowly with a half-life of more than 16 min. Valinomycin, nonactin, A23187, X-537A (lasalocid), bromo-lasalocid, and carbonyl cyanide m-chlorophenylhydrazone did not exhibit these effects at concentrations at which they did not inhibit protein synthesis of the cells.
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002222:Carbamoyl-Phosphate Synthase (Ammonia) / Q000378:metabolism*; D002460:Cell Line; D003600:Cytosol / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism*; D007476:Ionophores / Q000494:pharmacology*; D007700:Kinetics; D008025:Ligases / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008715:Methionine / Q000378:metabolism; D008930:Mitochondria, Liver / Q000201:enzymology; D008985:Monensin / Q000494:pharmacology; D009550:Nigericin / Q000494:pharmacology
chemical_list: D004792:Enzyme Precursors; D007476:Ionophores; D008985:Monensin; D008715:Methionine; D008025:Ligases; D002222:Carbamoyl-Phosphate Synthase (Ammonia); D009550:Nigericin