ALCOHOLIC FERMENTATION 275 



been isolated from fermentations of glucose by yeast 

 extract in presence of mono -iodo acetate which inhibits 

 their further breakdown ; equilibrium is established 

 between them when the appropriate enzymes are present ; 

 they are rapidly fermented by yeast extracts. The 

 breakdown of phosphoglyceric acid to pyruvic acid and 

 phosphoric acid is inhibited by sodium fluoride so that 

 phosphoglyceric acid accumulates when fermentations 

 are conducted in its presence. Both 2- and 3 -phospho- 

 glyceric acids have been isolated from muscle extracts 

 and so also has phosphopyruvic acid. Adenylic acid and 

 adenosine triphosphate have been isolated from yeast 

 juice and shown to react with fructose- l:6-diphosphate. 



According to Meyerhof's scheme glucose is phos- 

 phorylated by a transfer of phosphate groups from 

 adenosine triphosphate : — 



I I 

 CH C— N 



li II ^. 



II II >CH OH OH OH 



II II ^ III 



N C— X CH— CHOH.CHOH.CH.CH2— 0— P— 0— P— 0— P— OH 



I 1 11 II 11 



u 



to give first hexosemonophosphate and then hexose 

 diphosphate. At the same time the adenosine triphos- 

 phate is converted through the diphosphate to adenosine 

 monophosphate or adenylic acid : — 



X=-=:C'.NH., 



I I 

 CH C— X 



II II %CH 9^ 



II II /^^ I 



N C— N CH.CHOH.CHOH.CH.CH2.O.P— OH 



I I 11 



The liexose diphosphate (fructose- I : G -diphosphate), 

 under the infhience of the enzyme zymohexase, breaks 



