9^ 



uncoupled completely by iodide in a 0.03 M concentration, while 

 O2 uptake remained uninhibited. Bromide had a similar action, but 

 corresponding to its weaker quenching abilities had to be applied 

 in higher concentration to produce the same effect. 



These results are at variance with those obtained by Klemperer, 

 who found iodide without effect on oxidative phosphorylation. 



^ 100 



80 



c 

 o 





60 - 



40 - 



20 



c 

 .2 



3 



E 



-20 



CI M 0.04 

 I M 



0.035 

 0.005 



0.03 

 0.01 



0.025 

 0.015 



0.02 

 0.02 



0.015 

 0.025 



0.0 1 

 0.03 



0.005 

 0.035 





 0.04 



Fig. 23. Effect of replacing the chloride by iodide in the saline on 

 oxidative phosphorylation of rat liver mitochondria, expressed in % of 

 control in 0.04 M chloride. Open circles: phosphorylation. Full circles: 

 oxygen uptake. 



His technique of isolation of mitochondria was somewhat differ- 

 ent and probably superior to ours. Possibly, his negative results 

 were due to the mitochondrial membrane, which might have been 

 preserved better in his experiments and might have kept the 

 iodide out. The seats of oxidations are, apparently, not readily 

 accessible to iodide. This may explain why somewhat higher con- 

 centrations of iodide had to be used to arrest phosphorylation 

 than was expected. 



As mentioned earlier, riboflavine frozen in the presence of 

 10"* M iodide has a brownish color which suggests a direct transi- 



