97 



more strongly than the phenol, arresting it at a lower coficentra- 

 tion. But the curves also show that while the nitrophenol, at a 

 low concentration, increases the oxygen uptake, the reverse effect 



150 



too 



o 50 



o 



5>P 



*% 



• • 







250 



DNN 



a 



500 



250 

 DNP 



b 



500 



250 



OOP 



c 



500 



Fig, 24. The effect of dinitronaphthol (a), dinitrophenol (b), and 

 dichlorophenol (c) on O2 uptake (open circles) and oxidative phospho- 

 rylation (full circle) in rat liver mitochondria. 



is observed with the naphthol, which moderately decreases oxida- 

 tion. All the same, the inhibition of phosphorylation could not 

 be ascribed to the lack of oxidation, for the oxygen uptake still 

 present would have sufficed to maintain phosphorylation at its 

 original level. Dinitronaphthol has more specific solubilities than 

 dinitrophenol, having more affinity to lipides and less to water. So 

 it may be accumulated by certain cell constituents and have biologi- 



