Enzymes and Fermentation in Yeast Cells 285 



attributed to a change in the distribution of the available 

 phosphorus between orthophosphate and bound phosphates. 



Reoxidation of reduced triphosphopyridine nucleotide, 



a bottleneck in the oxidative pentose phosphate cycle 



(Holzer and Witt, 19586) 



The analysis shown in Fig. 6 reveals the presence of another 

 regulative mechanism which starts after NH"^ ions have been 

 added to glucose-oxidizing yeast. Besides the changes 



ketoglutaratQ 



^ fructose diphosphate 



•->— • glucose-6-phosphate 



20' 25' 



minutes after odditjon of glucose 



Fig. 6. Changes in concentrations of TPN, glucose-6-phosphate, 

 and other metabolites after the addition of NH^ ions to glucose- 

 oxidizing yeast cells (From Holzer and Witt, 19586. Reproduced 

 by permission of the Editors, Angew. Chem.). 



