Glycolysis and the Pasteur Effect 211 



Table V 



32p UPTAKE BY ASCITES TUMOUR CELLS 



Cells (30 mg. protein) were incubated with ^^P — Pi (20,000 cpm/(xmole8) at 

 30°C for 30 minutes. 



intracellular concentration of Pi is a major limiting factor of 

 glycolysis. The entrance of Pi into the cell appears to depend 

 on an energy-yielding process and is sluggish compared to the 

 rate of glycolysis. 



In consequence of the above, the addition of glucose to 



Fig. 1. Rate of glucose uptake and changes in intra- 

 cellular concentrations of ATP, ADP and Pi 

 Glucose (3-7 (jtmoles/ml.) wa^ added after 5 minutes of 

 preincubation at 30°. Results are expressed as jj.moles/ 

 ml. of packed cells. 



ascites cells results in a continuous lowering of the intracellular 

 Pi level until a new steady state is reached as shown in Fig. 1. 

 As expected from the high Pi concentration, the initial uptake 



