48 



Discussion 



went on to show that since what is in the mitochondria is so small in 

 comparison with the total in the flask then this does not, in fact, measure 

 the ratio of the nucleotides inside the mitochondria. The experiments 

 that were done on the conversion of ornithine to citrulline permitted the 

 conclusion that on the ascending limb of the oxygen uptake curve there 

 was a lower ATP : ADP ratio within the mitochondria as deduced from 

 the intramitochondrial conversion of ornithine to citrulline. 



Chance: On the question of the relationship of the endoplasmic 

 reticulum to the mitochondria and the existence of a cytoskeleton, Dr. 

 Siekevitz, you have postulated some organization of the cytoplasm 



fiL/mg. PROTEIN/hn 

 ,00 



LIVER MITOCHONDRIA 

 PYRUVATE 



NUCLEOTIDE 



n5 



Oa UPTAKE 



ADP^ 



AMP 



3xIO-6m 



CONCENTRATION OF DNP. 



Fig. 1 (Aldridge). The effect of 2 : 4-dinitrophenol upon the oxygen 



uptake and nucleotide concentration when liver mitochondria are oxidizing 



pyruvate. Oxygen uptake was measured between 10 and 30 min. and 



nucleotide concentrations at 32 min. after addition to the bath at 37°. 



with respect to the mitochondria. We agree with Bartley's comments 

 (see p. 46, above), Also, Dr. Bo Thorell of the Pathology Department, 

 Karolinska Institute, and I did the following simple experiment. In the 

 ascites tumour cell there is a delicately balanced regulation initiated by 

 adding glucose to the cells as taken from the mouse. This regulation 

 apparently involves some intimate relationship of cytoplasmic and 

 mitochondrial enzymes. We centrifuged the cells in gum arable for 

 60 minutes at the top speed of the Spinco centrifuge, so as to separate 



