284 



Helmut Holzer 



rapid rise of the orthophosphate concentration is brought 

 about. The increase in the orthophosphate concentration 

 gives rise to an accelerated triose phosphate dehydrogenation 

 followed by an increase in the pyruvate and acetaldehyde 



orthophosphate 

 pyruvate X ~ 



«-ketogLutarate « j 



acetaldehyde 



, > minutes after addition of glucose 



Fig. 5. Changes in concentrations of carbohydrate 

 metabohtes after the addition of NH^ ions to ghicose- 

 oxidizing yeast cells. (From Holzer and Witt, 1958a. 

 Reproduced by permission of the Editors, Biochem. Z.) 



concentration (Fig. 5). The accelerated pyruvate decarboxyla- 

 tion is revealed manometrically as an increase in aerobic 

 fermentation. 



After the rapid rise of orthophosphate concentration there 

 is a rapid drop to small concentrations. During this latter 

 period the orthophosphate concentration cannot be respons- 

 ible for the increased aerobic fermentation which lasts for a 

 long time after the addition of NH/ ions. At present we are 

 attempting to solve the problem of whether this may be 



