Transport of Pyruvate in Mitochondria from Different Tumor Cells1
نویسندگان
چکیده
A comparative study of the transport of pyruvate in mitochon dria isolated from normal rat liver and from three tumors has been carried out. The Kmfor net pyruvate uptake in mitochondria isolated from Ehrlich ascites tumor cells is practically equal to that measured in normal rat liver mitochondria while, on the other hand, it is higher in Morris hepatomas 44 and 3924A. The Vm» of pyruvate uptake is depressed in all three types of tumor mitochondria as compared to that in the rat liver mitochondria, with the depression being higher in Morris hepatoma 3924A mitochondria. The lower activity of pyruvate translocator in mi tochondria isolated from tumor cells as compared to that in rat liver mitochondria is also shown by depression of the rate of pyruvate-supported oxygen uptake. The results document a decreased activity of the pyruvate translocator in tumor mito chondria which seems to be correlated with the growth rate of the tumor cells.
منابع مشابه
Transport of pyruvate in mitochondria from different tumor cells.
A comparative study of the transport of pyruvate in mitochondria isolated from normal rat liver and from three tumors has been carried out. The Km for net pyruvate uptake in mitochondria isolated from Ehrlich ascites tumor cells is practically equal to that measured in normal rat liver mitochondria while, on the other hand, it is higher in Morris hepatomas 44 and 3924A. The Vmax of pyruvate upt...
متن کاملThe proton stoichiometry of electron transport in Ehrlich ascites tumor mitochondria.
Initial rate measurements of the stoichiometric relationships between H+ ejection, K+ and Ca2+ uptake, and electron transport were carried out on mitochondria from Ehrlich ascites tumor cells grown in mice. With succinate as substrate and N-ethylmaleimide to prevent interfering H+ reuptake via the phosphate carrier, close to 8 H+ were ejected per oxygen atom reduced (H+/O ejection ratio = 8.0);...
متن کاملEnhanced rate of citrate export from cholesterol-rich hepatoma mitochondria. The truncated Krebs cycle and other metabolic ramifications of mitochondrial membrane cholesterol.
Mitochondria isolated from rapidly growing, poorly differentiated Morris hepatoma 3924A have been found to export the citrate they generate from pyruvate, at a rate greater than four times that of control liver preparations. These 3924A mitochondria fail to exhibit state 3 respiration when either pyruvate or citrate are supplied as respiratory fuels. Nevertheless, substrates that join the Krebs...
متن کاملRegulation of citrate transport and pyruvate dehydrogenase in rat kidney cortex mitochondria by bicarbonate.
1. Bicarbonate increased citrate and 2-oxoglutarate accumulation when rat kidney cortex mitochondria were incubated with pyruvate or L(-)-palmitoyl carnitine in the presence of L-malate. 2. Bicarbonate stimulated the exit of citrate from mitochondria. The Km for bicarbonate was 13.5 mM and the Vmax was 0.59 nmol/min/mg of protein at 10 degrees. 3. The bicarbonate-stimulated exit of citrate from...
متن کاملINHIBITION BY a-CYANO-4-HYDROXYCINNAMATE AND EVIDENCE FOR SEPARATE IDENTITY FROM THE PYRUVATE TRANSPORTING SYSTEM OF MITOCHONDRIA*
Some of the known inhibitors of pyruvate transport inhibited the activity of carnitine-acylcarnitine translocase. Their order of effectiveness, with millimolar concentration required for 50% inhibition given in parentheses, was: Compound UK-5099 (cz-cyano+(l-phenylindol-3-yljacrylate) (0.1); cu-cyano-4-hydroxycinnamate (0.17); a-cyano-3-hydroxycinnamate (1); cu-cyanocinnamate (1); cu-fluorocinn...
متن کامل