288 



Discussion 



iodoacetate is added in order to simulate the lack of DPN. This con- 

 dition is illustrated in Fig. 1, which shows the kinetics for fructose 



^JM 



• •DHAP 



FDP 



5- 



>ATP 



»ADP 



Fig. 1 (Hess). Steady state change of concentra- 

 tion during transition from endogenous to glucose 

 metabolism in the presence of 1-7 mM iodoactate. 

 Concentrations are given in {XM/g. wet weight. 

 Glucose, 0-75 mM. 



diphosphate, dihydroxyacetone phosphate, adenosine diphosphate and 

 triphosphate. 



Chance : Since the lack of DPN has been postulated to be the cause of 

 this metabolic control and since we have for some time been studying 

 the pyridine nucleotide kinetics in yeast cells following the addition of 

 glucose to the starved cells, it is possible that our data may shed some 

 light on the question raised by Prof. Holzer's results and by Dr. Racker. 

 The typical response of reduced pyridine nucleotide to glucose addition 

 under aerobic and anaerobic conditions is shown in Fig. lA and B. 



