INTERMEDIATE CARBOHYDRATE METABOLISM 9 



glycolysis is suppressed. In the picture outlined above the oxygen 

 used would automatically eliminate an equivalent lactic acid forma- 

 tion, in so far as the oxygen serves to reoxidize dihydrocozymase. But 

 we must have in mind that the oxygen intervenes only indirectly by 

 way of the oxidizing catalysts. Here the so-called "Pasteur enzyme" 

 assumed by Warburg (20) and demonstrated by Stern and Melnick 

 (21) plays its role in steering the oxidation. All oxidation not going 

 by the way of cozymase would be without "Pasteur effect"; it may 

 be oxidation of non-carbohydrate, which replaces sugar oxidation, 

 or it may be oxidation of sugar by way of triphosphopyridine nu- 

 cleotide. 



Now we come to the second half of the problem, the actual con- 

 version of lactic acid to glycogen in the oxidative recovery of the 



Glycogen (starch) 

 HaPO, If 



Glucose-1-phosphate 

 (Cori-Ester) 



Dihydroxyacetonephosphate 

 I- (a) -Glycerophosphate 

 (Glycerol -1- H3PO4) 



Pyruvic acid + H3PO4 



■J' 

 Phosphopyruvic acid (?) (hydrated) 



H2 J, 

 Phosphoacetic acid -1- CO2 



i 

 Acetic acid -f H3PO4 



Acetaldehyde -|- CO2 <- 

 Ethyl alcohol 



d-Glucose + H3PO4 

 -* Glucose-6-phosphate 

 Fructose-6-phosphate 



H3P04|f 



Fructose-l ,6-diphosphate 



-» d-3-Phosphoglyceraldehyde 



H3PO4JI 

 d-1 ,3-Diphosphoglyceraldehyde 



d-l,3-Diphosphoglyceric acid 

 H3PO4II 

 <f-3-Phosphoglyceric acid 



It 

 d-2-Phosphoglyceric acid 



H2OII 

 enol-Phosphopyruvic acid 



Pyruvic acid -1- H3PO4 



HJt 



Lactic acid 



Figure 1. — Complete sequence of intermediaries in anaerobic breakdown 



of carbohydrate 

 Insertion on the left: oxidative decomposition in lactic acid bacteria, accord- 

 ing to Lipmann ( 18 ) . 



