Metabolism of Ascites Tumor Cells. Iii. Effect of 2-deoxyglucose Phosphorylation on Phosphorus Metabolism.

The phosphorylation of 2-deoxyglucose by respiring Krebs-2 ascites tumor cells and the effect of 2-deoxyglucose metabolism on cell orthophosphate, acid-labile phos phate, and adenine nucleotide-phosphate in these cells was investigated. In the presence of 2.0 mM orthophosphate 2-deoxyglucose (2DG) was taken up initially very rapidly, 5.7 /umoles/min/ml of cells, but uptake fell off to a steady state rate of less than 5 per cent of this rate after 20 minutes. Most of the 2-deoxyglucose taken up by the cells was accounted for as 2-deoxyglucose-6-phosphate under these conditions. Orthophosphate was also taken up by the cells incubated with 2-deoxyglucose at a rate which approximated that of steady-state 2-deoxyglucose uptake. In a medium to which no orthophosphate had been added, over-all 2-deoxyglucose uptake was dimin ished, and the orthophosphate content of cell suspensions was found to have fallen to half its original value within 30 seconds after addition of 2-deoxyglucose. Cellular acid-labile phosphate and adenosine high-energy phosphate were also found to have fallen to 46 and 23 per cent of the original concentration of each within 2 minutes after the addition of 2-deoxyglucose. There was a net loss of 65 per cent cellular adenine nucleotides within 12 minutes after addition of 2-deoxyglucose.