Rate-Limiting Factors in Ethanol Oxidation by Isolated Rat-Liver Parenchymal Cells Effect of Ethanol Concentration, Fructose, Pyruvate and Pyrazole

摘要: 1. Isolated rat-liver parenchymal cells oxidized ethanol at a rate of 1.4, 1.7, i.9 and 2.5 p.mol/ min per ml packed 4, 20, 40 65 mM ethanol, respectively. Between an abrupt 30°/, increase in the oxidation was observed. 2. The activity NAD-dependent alcohol dehydrogenase homogenate isolated corresponded to 1.25-5 U/ml cells, depending on assay method used. 3. Fructose or pyruvate enhanced by 1.4-2.0 pmol/min independent concentration applied. No additive effect two compounds upon 4. Pyrazole inhibited NAD dependent as well unstimulated fructose-stimulated with Ki-value 9-13 pM. pyrazole concentrations, which only 30 Ole, indicating that “fructose effect” is mediated via deh y drogenase . 4mM slightly part not catalyzed dehydrogenase, whereas 18 also this pathway significantly. 5. 50 pM had no all basal inhibited. 6. results concerning fructose are interpreted terms mechanism for reaction dehydrogenase. At low concentrations absence fructose, rate-limiting step appears be dissociation enzyme-NADH complex, whereas, presence maximal may ethanol. 7. suggest enzyme systems other than participate