PASTEUR EFFECT 



69 



Pasteur eflFect. In harmony with this generahzation is the increase 

 of the Pasteur effect in tumors by ferricyanide (70) and in yeast by 

 indophenols (71). The complexity of the dye effects, however, is il- 

 lustrated by the action of methylene blue, which, according to early 

 observations by Gerard (72), releases aerobic glycolysis in muscle, 

 while it was found by Barron (73) to inhibit aerobic glycolysis in 

 erythrocytes. Nevertheless there seems to be a parallelism between 

 dye action in extracts and in cells and a correlation between thiol 

 and dye effects. 



PASTEUR EFFECT WITH VERY LOW RESPIRATION 



That aerobic inhibition of fermentative metabolism is inde- 

 pendent of respiration can be most clearly demonstrated through 

 the occurrence of the Pasteur effect with very low respiration. 

 Aside from the dye-induced Pasteur effect in extracts, some examples 

 of such phenomena in living cells have already been discussed, such 

 as inhibition by traces of oxygen or inhibition in the presence of 

 relatively low respiration in yeast (11, 12). As a rule parallelism 

 between the appearance of anaerobic metabolism and the dis- 

 appearance of respiration is to be expected by the very nature of 

 the phenomenon. The fact that the most-used inhibitors of respira- 

 tion are metal-specific and are likewise more or less pronounced 

 inhibitors of the Pasteur reaction, has greatly complicated the 

 analysis. Inhibitors of respiration which interrupt the chain, not at 



Table 9.— Pronounced Pasteur effect with very low respiration 



