150 CONTROL MECHANISMS IN CELLULAR PROCESSES 



about the fructose phosphate levels. Kvamme (1958cl) found that 

 fructose phosphates are considerably higher aerobically than anaer- 

 obically in ascites cells. This difference is accentuated at high phos- 

 phate concentrations; yet the Pasteur effect is less under these con- 

 ditions, or in fact reversed. On the other hand, when cells were 

 inhibited by malonate and made to respire fumarate, the phospho- 

 fructose levels were reversed. Kvamme concluded, however, that 

 apart from the effect on fructose phosphate there is no fundamental 

 difference between the two types of Pasteur reactions. He there- 

 fore limited the explanation solelv to competition for inorganic phos- 



TABLE 5-2 

 The Effect of Dinitrophenol on Valine-1-C^^ Incorporation in Yeast 



Atmole Glucose /imole Oo Valine Incorporation 



Utilized Uptake cpm/planchet 



Zero time 5 



Control 17.4 14.0 4,109 



+ Dinitrophenol 21.6 15.1 3,525 



Each flask contained 30 ^mole of glucose; 1 ^niole valine-1-Ci^ (specific activity 10^ 

 cpm/fimole); citrate buffer, pH 6.0, 30 ^mole; baker's yeast 6 mg in a final volume 

 of 3.0 ml. To the appropriate flask, 0.15 /^mole of dinitrophenol were added. At the 

 end of the incubation time (70 min.), the yeast was centrifuged out and diluted with 

 additional cells; the proteins were precipitated with trichloroacetic acid. After the 

 proteins were washed free of absorbed \'aline, they were counted at infinite thickness. 



phate. Yet he found that complete inhibition of triose phosphate 

 dehydrogenase with iodoacetate abolished glucose uptake anaero- 

 bically but not completely aerobically, thus indicating that glucose 

 uptake can proceed in the absence of glycolysis. This is again an 

 argument that phosphate competition alone is not an explanation 

 for the total Pasteur reaction. Furthermore, in homogenates Terner 

 (1954) found that the level of inorganic phosphate was such that 

 it could not mediate the pronounced Pasteur reaction in his prepara- 

 tions. And as mentioned before, Wu and Racker (1959b) found 

 inorganic phosphate levels well above the Km for triose phosphate 

 dehydrogenase in ascites cells. Even under conditions where inor- 

 ganic phosphate is not the obvious explanation, nitrophenols alleviate 

 the effect (Terner, 1954, 1956; Wu and Racker, 1959b; Meyerhof 

 andFiala, 1950). 



There are doubts whether the effects of dinitrophenol are as clear 

 as generally assumed. Ronzoni and Ehrenfest (1936) found that 



