282 



Helmut Holzer 



with high activity. This causes the fructose diphosphate con- 

 centration to increase still more than under normal conditions. 

 Finally, further evidence, showing that addition of acetal- 

 dehyde accelerates the triose phosphate dehydrogenation, is 



100«/o N2 

 oeetoldehyde 



sec. 



Fig. 4. Concentrations of pyruvate after the addition of glucose to 



starved yeast cells (From Holzer and Freytag-Hilf, 1959. Reproduced 



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



obtained on examining the behaviour of the pyruvate con- 

 centration (Fig. 4). Without acetaldehyde, under anaerobic 

 conditions a slow, constant rise of the pyruvate concentration 

 takes place during the first 25 seconds, resulting in a value 

 which, on the whole, remains constant. On the addition of 

 acetaldehyde, however, a rapid increase of pyruvate is ob- 

 served, undoubtedly depending on the fact that the decom- 



