Contribution of diffusion to the oxygen dependence of energy metabolism in human neuroblastoma cells.
In suspensions of normally respiring human neuroblastoma cells respiration has an oxygen dependence similar to that of suspensions of isolated mitochondria in a comparable metabolic state. When mitochondrial oxidative phosphorylation is uncoupled, respiration at limiting oxygen pressures is indicative of the oxygen pressure difference between the extracellular medium and the mitochondria. Diffusion gives a P50 proportional to the cellular respiratory rate, with a value of 0.15 torr for the respiratory rate of normal cells. The oxygen pressure difference between the cytoplasm and the mitochondria is probable only a few tens of millitorr.
Department of Biochemistry and Biophysics, Medical School, University of Pennsylvania, Philadelphia 19104.
W L
WL
Rumsey
M
M
Robiolio
D F
DF
Wilson
D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D004058:Diffusion; D004734:Energy Metabolism; D006801:Humans; D007700:Kinetics; D009447:Neuroblastoma / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D014407:Tumor Cells, Cultured / Q000378:metabolism*
D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone