648 



Messrs, Harden and Norris. 



Fermentation of [July 18, 



V. Fermentation of Galactose hy Yeast-juice in presence of Phosphate. Relation 

 of extra Carhon Dioxide evolved to Phosphate added. 



The addition of phosphate to a fermenting mixture of galactose and yeast- 

 juice produces an acceleration in the rate, and an extra amount of carbon 

 dioxide is evolved which is equivalent to the phosphate added. As in the case 

 of glucose, the phosphate is converted into an organic compound which cannot 

 be precipitated with magnesium citrate mixture. The compound formed can 

 be isolated in the form of its lead salt as described by Young for glucose.* 



The extra carbon dioxide was evolved much more rapidly in the case of 

 glucose than with galactose with the particular sample of juice employed. 



Experiment 15. — Two quantities of 25 c.c. yeast-juice were incubated with 

 1 gramme of the sugar under investigation until a constant rate was 

 obtained and 2"5 c.c. of a 0"3 molecular solution of sodium phosphate then 

 added to each. 



Table V («). — Acceleration of Eate of Fermentation of Galactose and Glucose 

 by Yeast-juice on addition of Phosphate. 



Experiment 15. 



Time after addition of 

 phosphate, in minutes. 



COj evolved in preceding 5 minutes. 



Galactose. 



Glucose. 



(Rate previous to addition) 



0-8 



1-3 



5 



5 -3 



8-3 



10 



3-6 



7-9 



16 



3 -4 



5-7 



20 



2-8 



2-6 



25 



2-4 



1 -9 



30 



2-5 



1 -3 



3g 



2-1 



1 -3 



40 



2 0 





45 



1 -8 





50 



1-5 





65 



0-9 





Table V (&).— Equivalence of extra CO2 evolved to Phosphate added in above 



Experiment. 





Oahictose. 



Glucose. 



Correction for rate without phosphate 

 „ at N.T.P 



5-3 

 0 -9 



29 •! in 1 hour 

 10-8 

 18-3 

 16 -7 



8-3 

 1 -3 



27 "7 in 30 mins. 

 7 -8 

 19 -9 

 18-2 



* ' Roy. See. rroc," B, 1909, vol. 81, p. 528. 



