142 



PHYSIOLOGY OF THE FLi.XGI 



to the scheme of gUicose dissimilation presented in schemie VI (Meyerhof, 

 1938, 1949). Further information about these reactions may be found in 

 Sumner and Soraers (1947), Tauber (1949), and Prescott and Dunn 



(1949). 



Scheme VI. The Pathway of Glucose Dissimiliation by Yeast (Alcoholic 

 Fermentation) and Muscle (Glycolysis) 

 (Courtesy of Meyerhof, WaUerstein Labs. Communs. 12 : 256, 1949. Published by 

 permission of WaUerstein Laboratories.) 

 Glycogen, starch D-Glucose 



± H,P04 



II 



+ H3PO4 



Glucose- 1-phosphate (Cori ester)^=±GIucose-()-phosphate (Robison ester) 



Fructose-6-phosphate (Neuberg ester) 



+ H3PO4 



'4' 



Fructose-ljG-diphosphate (Harden- Young ester) 



Dioxyacetone phosphate* 



+ H2 



CHaOHCiOCHrOPOsHa 



/-Q^Glycero phosphate 



[CHsOHCHOH-CHaOPOsHs 



Glycerol + H3PO4 



Aceta 

 Ethanol 



dehyde + C02< 



Kd) 3-GIyceraIdehyde phosphate (Fischer-Baer 



ester) 

 tCHOCHOHCH2-0-P03H2 



+ H2 



+ H3PO4 

 (d) 1,3-Diphosphoglyceric jicid 

 + H3PO4 



'CO-O-POsHsCHOH-CHa-O-POsH, 



(d) 3-Phosphoglvceric acid 



TCOOH-CHOH-CHa-O-POsHs 



(d) 2-Phosphoglvceric acid 



* CH2dHCH(OP03H2)COOH 



+ H2O 



(Enol)-Phosphopvruvic acid 



TCH2:C(OP03Ho)(COOH) 



-Pyruvic acid + H3PO4 . 



±H2 



Lactic acid 



Pyruvic acid is a key intermediate compound in metabolism. Pyruvic 

 acid serves as a source of carbon for many fungi, although the rate of 

 growth on this substance is frequently slow. This is in accord with the 

 hypothesis that intermediate metabolites are able to replace the original 

 carbon source. The accumulation of this compound in the culture 

 medium may be demonstrated by the formation of iodoform in the cold 

 by adding a solution of iodine and making the medium strongly alkaline. 

 The sensitive color test of Lu (2,4-dinitrophenylhydrazine) may also be 

 used [see Friedemann and Haugen (1943) for details]. Acetaldehyde also 

 yields iodoform under these conditions, but gentle heating will drive off 



