Bacfenal Metabolism 75 



lated as the crystalline sodium salt and identified as 2-keto, 

 3-desoxy, 6-phosphogluconate (Figure 5). This substance is 

 then split enzymatically to pyruvate, which is derived from 

 carbon atoms I to 3 of glucose, and 3-phosphoglyceralde- 

 hyde, derived from carbon atoms 4 to 6. The same reactions 

 occur in Pseudomonas fluorescens (14). 



A closely related sugar decomposition mechanism has 

 been detected in a fermentative bacterium, Pseudomonas 

 lindneri, by the tracer method. This organism carries out 

 a typical alcoholic fermentation in so far as the products 

 are concerned. The experiments of Gibbs and DeMoss (5) 



C'^GLUCOSE Ps. lindneri YEAST 



'^CHO XO. 'CH3 



•CHOH •CH2OH CH2OH 



^CHOH ^%Wj, ^COa 



4hoh V02 ^Cp2 



CHOH CH2OH CH2OH 



CHgOH °CH3 CH3 



o 



FIGURE 6. Alcoholic Fermentation by Pseudomonas lindneri, after Gibbs 



and DeMoss (6) 



show, however, that the carbon dioxide is derived from 

 carbon atoms 1 and 4 of glucose; the carbinol group of 

 ethanol comes from carbons 2 and 5, and the methyl group 

 from carbons 3 and 6 of glucose (Figure 6). This carbon 

 distribution pattern is completely different from that ob- 

 tained with yeast and is sufficiently similar to that observed 

 with Pseudomonas saccharophila to suggest that both organ- 

 isms use the same mechanism for converting glucose to 

 three carbon units. But further work with cell-free extracts 

 will be necessary to establish this possibility. 



